Skipper Shelton's brother is on a boat with his crew.
Kelper: Let's hope old Neptune has been kind to us this time.
The crew pulls up an empty net.
Kelper: Salty scallops, empty again! I hate to say it, but our only choice now is Dead Man's Point.
Crew Member 1: But isn't Dead Man's Point haunted?!
Kelper: Aye, 'tis what they say, and we probably won't come back alive. But don't forget, we're fishermen. We do stupid things all the time!
They reach Dead Man's Point and a fog rolls in.
Kelper: This fog is thicker than sea poop. Always slays me sea poop.
The crew pulled up the net full of fish.
Kelper: Now that's more like it!
Something swims behind him.
Kelper: Huh? What in the world?
Something cuts the net freeing the fishes and multiple Fish Freaks land on the ship. The two crew members ran.
Crew Member 1: The legend is true! Fish Freaks!
They surround them as they run but another one breaks through the floor and screeches.
Kelper: We're doomed!
The Fish Freaks surround them again and attack.
At the Crstal Cove Spooky Muesum Daphne is with Y/N.
Daphne: I love the haunted museum when it's empty. It reminds me so much of us. Oh, look, flim flam! Remember him, Y/N?
Y/N: Yeah, I miss the kid. He was clever.
Daphne: Ohh, so tragic. stretch, even for a pre-teen con artist.
Daphne then sees a statue of Scrappy Doo.
Daphne: Wow, I haven't seen-
Y/N: Nope. Not a word, Daph. We all promised each other that we would never speak of him, not after what he did.
They walk away. Night came and Shaggy and Scooby were at the Bloody Stake as the waitress comes over with more food.
Waitress: The manager says this is the last main course platter for you guys.
Shaggy: But, like, this is your all- you-can-gorge night. You have to keep feeding us.
Scooby: Yeah, that's right.
Waitress: All-you-can-gorge only applies to amateur diners. You guys are pros.
Shaggy: Well, she's got us there, Scoob. You want to know how we do it, miss vampire waitress?
Waitress: I'll bite.
Shaggy: Like, we call it the all-gulp no-air eating technique. By building our lung capacity, we can hold our breath and literally inhale as much food as we want. Show her, Scooby Doo.
Scooby eats everything in a matter of seconds.
Waitress: You two have way too much free time.
At Velma's home she was on her computer.
Velma: Hey out there, mystery lovers. Velma here. No mysteries to report. Just another Friday night. I'm by myself, as usual, and you know what? That's ok. What's so bad about sitting in your room alone on a Friday night?
She breaks the keyboard and brings out another one as she gets mail.
Velma: "Dear Mystery, Incorporated." Have you looked into the case of the missing sardine boat that disappeared off Dead Man's Point? I think it might have something to do with the haunted oil platform in the area. "Signed, Anonymous. " Jinkies, a mystery!
Velma calls the gang.
Velma: Hello, Daphne? Velma. Just got a tip on our web page. Apparently, a sardine boat disappeared. What? Well, I guess it can wait. Yes, I know you're in love with Y/N.
She hangs up.
Velma: Velma, I'm so in love.
Velma calls Shaggy.
Velma: Scooby? Velma. Put Shaggy on. Because you're almost impossible to understand on a phone. Shaggy? Velma. I've got a mystery for us. This boat disappeared. What do you mean you can't come? Dessert? But you can have jellied eyeball cobbler any- hello? Hello? He hung up on me! Velma calls Fred.
Velma: Fred, it's me, Velma. A boat disappeared. We should investigate. You're making traps?
She hangs up.
Velma: They don't want to help me? Fine, I'll do it myself.
Velma takes Daphne's dad's boat and goes into Dead Man's Point.
Velma: I hope Daphne doesn't mind me borrowing her family's expensive boat. Great, it's gonna be impossible to find any clues in this fog.
She then hears a female sing.
???: My song fills your heart. From the depths of the sea. Please listen and learn. All you can learn from me.
Velma: Uh, who's there?
???: A friend, Velma. How do you know my name?
???: I know much about you and Mystery, Incorporated. For example, I know you struggle with being smarter than everyone; Think that you have a neck waddle, which is why you always wear a turtleneck; Were dumped by your boyfriend for a dog-
Velma: Ok, you know me.
She then sees a mermaid.
Velma: A mermaid?
???: I am the source of the anonymous tip that brought you out here.
Velma: Merfolk have the Internet? Wait, what am I saying? This is biologically impossible.
???: Please, Velma. I have nowhere else to turn. I'm all alone. I think you can understand that. Crystal cove is in danger. They're coming for me. Run, Velma, or they'll get you, too!
Velma: Wait, I don't even know your name.
Amy: It's Amy. I'm a friend, Velma. You have to trust me!
She leaves as Velma goes back to start the engine as a Fish Freak climbs on board. She then sees the Fish Freak as the boat starts up and she speeds up and knocks the Fish Freak off board. The other Fish Freaks follow her as one climbs on top, and Velma makes a hard brake and knocks the Fresh Freak off the boat as the others catch up but Velma speeds off. The next morning, Velma told the gang what happened.
Daphne: A haunted oil platform, a missing sardine boat, Fish Freaks? That's really scary.
Scooby: Tell me about it.
Shaggy: Yeah. Like, if I wore boots, I'd be shaking in 'em.
Fred: Mr. E's usually the only one we get tips from. This could be some kind of trap.
Y/N: You have no idea who the tipster is, Velma?
Velma: Uh, no, none. Hopefully Skipper Shelton can clue us in on all that other stuff.
The gang went to Skipper Shelton and told him what happened.
Skipper: A missing sardine boat, eh? Well, the only one that fishes these waters is run by me brother skipper Shelton.
Fred: There are two Skipper Sheltons?
Skipper: Besides meself, there are 5 Skipper Sheltons, all siblings of mine. A sardiner, a shrimper, a manta-rayer, a kelper, and sea-dragoner. But we don't talk about him, right, Wolfie?
Scooby: I have no idea what he's talking about.
Skipper: As far as haunted oil platforms and Fish Freaks go, Heh, that's a bunch of crazy sea tales.
Velma: But-
Skipper: The next thing you'll be telling me is that mermaids really exist.
The gang except Velma laughs.
Fred: We wouldn't go that far.
Soon after the gang drives off and Skipper goes inside as the Fish Freaks come onto the land.
Skipper: Haunted oil platforms and Fish Freaks? What will those crazy kids come up with next?
He then hears a growling outside.
Skipper: What in the 7 seas is making that racket?
Skipper goes outside with a flashlight and looks up and sees a Fish Freak and it attacks him. At Velma home, she waits for Amy to reply.
Velma: Come on, where are you?
She hears a knock on the window and sees Amy.
Velma: Amy?
She opens up the window and Amy climbs in.
Velma: How did you get here all the way from the ocean?
Amy: It wasn't easy. The last few yards, the neighborhood cats were stalking me something fierce.
Velma gets a message.
Velma: One second, Amy. I gotta log off. "See you all later. " A special friend just stopped by for a visit. "LOL". Wow, you came all this way just to see me?
Amy: I had to. Skipper Shelton has been taken by the Fish Freaks.
Velma: What? But we just left him!
Amy: I think they're headed for the oil platform.
Velma: Can you lead us out there?
Amy: Sure, I guess.
Velma: Great, I'll call the gang.
There is a knock on the door. It was Velma's mom.
Angie: Velma, it's mom. Open up, honey. I want to meet your special friend.
Velma: Uh, what special friend?
Angie: The one you just wrote about on your blog.
Velma: Mom, you're so nosy.
Angie: Velma Dinkley, you open the door this instant!
Velma: Uh, how am I going to explain a mermaid in my room?
She drags Amy to the bathroom as closes the door as Angie opens the door.
Angie: Good thing I have this key I use to snoop around your room when you're not here. Oh, dear. Did I just say that out loud?
Velma: You have no respect for my privacy.
Angie: Ha! Of course, I don't. You're a teenager.
They then hear a crash in the bathroom.
Velma: I told you, there's no one here.
Angie goes to the bathroom and sees nothing inside.
Velma: Uh, see? I told you.
Angie leaves as Velma notices the window is open. At K-Ghoul, the gang was there.
Fred: Well, your anonymous tip checks out, Velma. Skipper Shelton is nowhere to be found.
Angel: You know, babies, I was wondering if this haunted oil platform is the same one that used to be owned back in the day by Destroido.
Daphne: The company with all those terrible products?
Angel: That's the one. They were going to start pumping oil a while back until some scientist dude shut them down over some, uh, environmental heebedy-jeebedy stuff.
Y/N: When was this?
Angel: About 20 years back.
Angel: I didn't know you lived here that long ago. I didn't. But, baby, I've always been interested in the environmental heebedy-jeebedy stuff. This story was real big back in the day, in all the papers.
Meanwhile Shaggy was reading the newspaper when he saw something.
Shaggy: Whoa! Like, check this out, you guys. Destroido's having a press conference tomorrow.
Angel: Might be worth paying them a visit.
The next morning, the gang goes to the press conference and sees Ed.
Ed: Ladies and gentlemen of the press, and smelly activists in need of a shower, Destroido is proud to announce our newest product, guaranteed to be a hot seller until we start getting sued. Gummy Dummies, fortified with extra lead. Gummy Dummies, the candy designed to inhibit brain function so you can relax in blissful ignorance. It comes in cherry, lime, and pork.
Shaggy and Scooby: Mmm, pork.
Daphne: What a terrible product!
Velma: That's Destroido for you.
Ed: I don't have any time for stupid questions, so grab some free samples and get lost.
He walks off as Shaggy and Scooby grab the free samples while the others go to Ed.
Velma: Mr. Machine, we'd like permission to go out to your abandoned oil platform for research purposes.
Ed: And I'd like to have a polka-dot princess pony, but mommy won't get me one. Now beat it before I have you arrested for trespassing.
He walks away as Ernesto and his group go towards the gang.
Ernesto: Nice guy, isn't he?
Y/N: Ernesto?
Ernesto: Hello again, comrade Daphne and Y/N. We have missed you on the front lines in our fight to take down the man.
Daphne: Gang, you remember mines and Y/N's radical idealist friend Ernesto from Daryl College.
Fred: Yeah! Hey, nice beret. What size is your head? I'm a seven and three-quarter, but I've got a head dimple in the back that makes it almost impossible to get a good snug fit. Heh.
Shaggy and Scooby walk towards them.
Shaggy: So, dude, like, what brings you here besides obvious evil?
Ernesto: We are here to protect Gaia, mother earth, from despotic corporate overlords like Destroido. Go, Gaia!
Crowd: Go, Gaia!
Velma: Yeah. Well, good luck with that. Come on, you guys. Just because Ed Machine said no doesn't mean we have to listen to him.
The gang walks away and gets on Daphne's father's boat and sails to No Man's Land,
Daphne: I don't remember daddy's little boat being so dinged up.
Y/N: No kidding.
The gang then sees the oil platform.
Scooby: Look over there.
Fred: Way to go, Scooby. I knew we'd find it eventually.
The pull up to the oil platform. Inside is abandoned, with no living soul in sight. The gang climbs up as they explore the abandoned oil platform.
Shaggy: Like, why couldn't we have come out here when it was nice and sunny? The problem with fog is you can't see anything until it's-
An abandoned atmospheric diving suit swings in scaring Shaggy and Scooby.
Velma: Relax, you babies. It's just an empty suite.
Scooby: We knew that.
Soon after, the gang is back at where they came not finding anything.
Shaggy: Like, can we go now? I don't know how this place could get any scarier.
Scooby: I do!
The Fish Freaks leap onto the oil platform.
Gang: Fish Freaks!
The Fish Freak surrounds them and captures them and ties them up.
Fred: Wow, look at these knots. The simplicity and the beauty. These Fish Freaks have skills.
Y/N: Fred, focus, please.
Shaggy: Like, what do they want with us? What if they eat my brains?
Y/N: It'll be a light meal.
Velma turns to the others who were captured.
Velma: But who are you?
Dr. Spike: Dr. Spike Cavanaugh. I used to be Destroido's chief of Geology.
Daphne: You're the scientist Angel was talking about.
Dr. Spike: The Fish Freaks nabbed me a couple of weeks ago, forced me to help them.
Skipper: Us, too. They've been making me and me brother work this rig like sea dogs.
Daphne: What are they up to?
Dr. Spike: They're going to drill for oil underneath this platform just like Destroido wanted to do years ago. But the ground here is so unstable that there's going to be a nasty oil spill if anyone drills into it. I tried to warn them, but they just wheezed at me and shuffled off.
Scooby: Why would fish freaks be interested in drilling for oil?
Dr. Spike: That, my canine friend, is the big greasy question.
A Fish Freak onto the platform with the others.
Dr. Spike: Please, I'm begging you not to drill. The oil will kill thousands of helpless sea creatures, which I think you kind of are, right?
They ignore him and walk away and activate the drill and they dive into the water.
Dr. Spike: Oh, this is terrible! We have to stop that drill.
Amy emerges.
Amy: Maybe I can help.
All: A mermaid?
Velma:
All: Amy?
Daphne: You know her?
Velma: Ok, yes. She was my source. But she's my secret special friend, so don't any of you think about stealing her. That was awkward.
Amy crawls up and unties the group and they are on the oil platform.
Velma: Dr. Cavanaugh, where's the off switch for that drill?
Dr. Spike: Uh, ahem, it's on the drill.
Scooby: That wasn't smart.
Dr. Spike: Yeah, I was never much of a details man.
Amy: Unfortunately, I damaged my tail pretty bad dragging myself up those steps, or I'd go after it.
Velma points to Shaggy and Scooby.
Velma: I recall you two bragging about how long you can hold your breath.
Shaggy: Like, that only applies when we're gulping massive amounts of chow.
Scooby: Yeah, chow.
Velma: Shaggy.
Daphne: Scooby.
Shaggy: But what about the Fish Freaks? They're, like, down there.
Fred: That's the best part. Once you turn off the drill, they'll chase you back up here, right into one of my traps.
Shaggy: Right. I get it. Once again, we're bait.
Daphne, Velma, Fred, and Y/N: Exactly.
Shaggy and Scooby put on diving suits, and they are lowered.
Scooby: Couldn't we wait 'till the water up?
Y/N: Nope.
Y/N pushes Shaggy and Scooby into the water.
Fred: Now let's trap some Fish Freaks!
The drill continues as Scooby and Shaggy swim towards the drill and press a button and stops the drill. The Fish Freak chases them as Shaggy and Scooby emerge. They are pulled up and onto the oil platform. They run as Amy sings.
Amy: Take another step closer for we still haven't met.
Fred: Now!
The trap activates and the Fish Freaks are caught in a net.
Amy: Too bad, you suckers, now you're caught in my net.
Daphne: Good job, Freddie.
Fred: Well, not one of my fancier traps, but I think there's a certain beauty in its simplicity.
Mr. Spike: I would like to see who's been holding me captive all this time.
He took off the masks and it was Ernesto and his friends.
Daphne and Y/N: Ernesto?
Ernesto: Hello, comrade Daphne, and Y/N and their fellow comrade mystery-solving teenagers.
Y/N: Wait aren't you against all this anti-environment stuff?
Ernesto: Funny you should ask. It all started when we were doing a little research into our old foe Destroido. We were going through their trash when we ran across some very interesting information. Dr. Cavanaugh's report on this giant oil deposit off Dead Man's Point. We came up with a plan to make enough money to fund our various protests. We were gonna drill for the oil ourselves and sell it.
Fred: You were doing this for cash?
Ernesto: You have no idea how expensive it is to be a grassroots activist! After we found the location of the oil platform, all we had to do was scare off anyone who started nosing into our business. And we would have, too, if that meddling mermaid had kept her fin to herself and never contacted you.
Velma: Hold on. Are you telling us that you were going to cause a major environmental disaster in order to get the cash to protest against major environmental disasters?
Ernesto: Yes! You must be willing to kill the environment to save it.
Gang: Uh no. I don't think that's right.
The police arrive and they are all brought back to land as Ernesto and the others were arrested. Velma turns and sees Amy out of her mermaid costume kissing Dr. Spikes.
Velma: Hey, you're not a mermaid!
Dr. Spike: Allow me to introduce my lovely wife Amy Cavanaugh, ordinary human and professional Commercial jingle singer.
Fred: That explains why your eerily beautiful singing voice made me want to put on deodorant!
Amy: Velma...
Velma: You lied to me. You acted like you were my friend, and I believed you.
Amy: I'm sorry. I came up with the mermaid character out of desperation. I'd gone to the police to report that my husband had been kidnapped by Fish Freaks, but they just laughed at me, then asked for directions to the oil platform so they could add it as a stop to on the Crystal Cove Mystery Tour. I thought that if I could make it sound like one of your mysteries, you'd help me rescue my husband. And you did.
Velma: How do you even know about us?
Amy: I read your blog. I'm a fan.
Velma: Does that mean you're going to stay in touch?
Amy: If you'd like to me to.
Velma: Well, whatever. It's your decision. But I wouldn't mind if you did. As far as helping, it's what we do. Our friend Angel also deserves a lot of credit. She knew about Destroido's involvement from some old newspaper articles. That's how we made the connection.
Amy: Newspaper articles? That's strange. Destroido covered the whole thing up. The papers never even knew about it.
Velma: Hmm.
At K-Ghoul, Angel was looking through some records when Velma emerged from the shadows scaring Angel.
Angel: Lordy, Velma! Baby, you just about scared me out of my skin-tight leather foxy pants. What's with all the sneaking around?
Velma: You tell me.
Angel: What's that supposed to mean?
Velma: For the short amount of time that you've been in Crystal Cove, you sure know a lot about this town's mystery history.
Angel: Well, I'm just curious by nature. Remember the heebedy-jeebedies?
Velma: Stop. One of my big problems, on a list that's long and distinguished, is that despite my skeptical nature, I trust people. I want to see the best in them. Unfortunately, they usually let me down. Things have been adding up for me, Angel. The help you gave us on this oil platform mystery, the diary you provided for the Mystery Manor case stuff that you shouldn't know and shouldn't have had, no matter what the heebedy-jeebedy.
Angel: What are you saying?
Velma: I'm saying Angel Dynamite isn't your real name. I think your real name is Cassidy Williams, and you're one of the members of the original Mystery, Incorporated, that vanished in the caves beneath Crystal Cove. Tell me I'm wrong friend.