Mayor Nettles wants the gang to investigate a house that's presumably haunted, according to some reports of the people in the neighborhood.
Mayor Nettles: Sorry to bother you so early, kids. But the neighbors have been calling in constantly with reports of unearthly moaning, inhuman howling, blood curling screams-
Shaggy: In other words, same old same old.
Fred: You can count on us, Mayor Nettles.
Daphne: We'll see if there's anything mysterious going on here.
Mayor Nettles: Thanks, kids.
She walks away.
Velma: Come on, come on, let's go! Let's get this over with.
Fred: After we're finished here, we need to relocate the Planispheric Disk.
Scooby: We'll do it.
Shaggy: Good idea, Scoob. Yeah, you and I will re-hide the disc while you guys check out the scary howls.
Daphne: You're out of luck, Shaggy. Remember? Y/N hid the disk last time. He's the only one who knows where it is.
Velma: Oy, can we hurry? Please?
Fred: Okay, let's get started. But, first, well, gang, it looks like we got another mystery on our hands! Come on, let's split up and look for clues?
Y/N was looking in the basement, there he finds a mirror, but he notices that his reflection is not normal, it moves differently. When Y/N turns around, his reflection pulls him into the mirror, causing Y/N to drop his lantern before he disappears.
The other members of the gang realized that the house wasn't haunted and went outside and called Mayor Nettles.
Velma: That's right, Mayor Nettles. The place wasn't haunted. Daphne found the neighbor's cat locked up in there. Poor thing had irritable bowel syndrome.
Scooby: Huh? Ugh. Yes.
Velma: That's why it was making all those terrible noises. No, you're more than welcome. It's twenty minutes past rendezvous time and still no Y/N. I'm virtually assured of my first tardy ever.
Daphne: What if he's hurt? Let's go back in and find him.
Shaggy: Like, I'm sure Y/N's fine, Daph. We were all over that house. And the only scary things we found were an unhappy cat and Scooby-Doo doing an impression of my mom using an old hat from the attic.
Scooby is wearing a wig.
Scooby: Oh, Norville. Eat all that broccoli or no television. It's all in the hat.
Fake Y/N: Hello, friends.
Daphne: Oh, Y/N. Thank goodness.
Fake Y/N: This place was a total bust. Nothing scary here. So, let's get to school before we're late. Punctuality is an important facet of learning.
Daphne goes to hug him by the fake Y/N walks past her.
Fake Y/N: Right, Daphne?
Daphne: Um, right, Y/N.
Fred: If I step on it, we can still make it to school on time.
Before Fred could enter fake Y/N got in the van instead.
Fake Y/N: I'll drive.
Fake Y/N hits the engine too hard.
Velma: Careful or you'll flood the engine.
Fake Y/N: Huh?
Velma: Tricky carburetor, remember?
Fake Y/N: Righty-o. Ok, let's roll-io.
They drive off as Shaggy and Scooby brings out a massive sandwich.
Fake Y/N: Hey, what do you two think you're doing?
Scooby: Having a little snack.
Fake Y/N: No eating in the van. Eating leads to crumbs. Crumbs lead to germs. Germs lead to sick days from work, secretly crippling the nation's economy.
Meanwhile the real Y/N wakes up.
Y/N: What just happened?
He goes upstairs and sees the whole house is destroyed.
Y/N: Guys? Gang! Daphne!
Y/N voice echoes as he pulls out his phone.
Y/N: "No signal anywhere."
Y/N ran through the streets as the sign to Crystal Cove in destroyed.
Y/N: Hello?! Anybody! Hello! Hello!
Y/n then sees skeletons all around the town.
Y/N: No, no, no, no. This is all wrong... Crystal Cove had fewer skeletons.
Y/N: Daphne! Fred! Velma! Shaggy! Scooby-Doo, where are you?
With the gang fake Y/N makes a pit stop.
Velma: What are you doing?
Fake Y/N: Making a stop.
He gets out as the five look at each other.
Scooby: Ugh, Y/N is acting funny.
Shaggy: And not like ha-ha funny, not funny at all.
Scooby: Yeah, freaky funny.
Fred: Something's wrong.
Daphne: I'm sure it's just a phase.
Fake Y/N exits and throws Shaggy the keys.
Fake Y/N: Norbert, catch. You drive.
Shaggy: Me drive? Norbert?
Daphne: Y/N, is there anything bothering you?
Fake Y/N: Bothering me? Not at all, dear girlfriend. I'm just listening to the baseball game. I love sports.
Daphne then talks to herself.
Daphne: "Girlfriend?" We're engaged.
She gets in as Scooby whines wanting a Scooby-Snack.
Fake Y/N: Does the dog need walking?
Scooby: I walk myself, Y/N.
Fake Y/N: Perhaps you would enjoy a canine crumpet.
Scooby: That is not a Scooby snack, Y/N.
Fake Y/N: What difference does it make? I'm sure they all taste the same.
Scooby is flabbergasted by what he heard and goes and lays on Velma.
Scooby: You eat 'em, then.
Fake Y/N: What was that, Scoobert?
Scooby: Uh, nothing. Nothing.
Meanwhile, the real Y/N is running through the city looking for any signs of life. He then sees the destroyed Mystery Machine.
Y/N: Okay so either one of two things are happening here, one, I was in a coma and did not age as everyone I love passed away, and I'm the only human, or two, I've finally gone insane... I'm thinking the second one.
Y/N then sees Fred's ascot, Shaggy's clothes, Velma's clothes, and Scooby's collar all lying on the floor, forgotten.
Y/N: Fred, Velma. Shaggy. Scooby. They're... They're... Oh, no. No. It's impossible. Can this day get any worse?!
Daphne scarf flies towards Y/N as he sees it.
Y/N: Daphne's scarf... No. It can't be. It can't be true. Daphne!
Y/N ran off to find any signs of life to no luck. He sits at City Hall looking at Daphne's scarf.
???: Y/N.
Y/N sighs and chuckles.
Y/N: Great, I'm hearing things now. I have officially gone insane.
???: Y/N, jeepies, is that really you?
Y/N looks up and sees an old woman, his mom.
Y/N: Mom?
M/N: Y/N, I've found you...
Y/N: Mom, is that really you?
M/N: Of course it's me, silly. I've been looking all over for you.
Soon after they start a fire as Y/N fixes the Mystery Machine.
Y/N: I still don't understand. I came out of that mirror, and everything had changed. Why is everyone a skeleton and how are you... alive?
M/N: When you didn't come back, something went crazy with the Planispheric Disk. Velma said it created a vortex around Crystal Cove and sped up time here. They searched everywhere for it. You hid it too well. Soon after, I was resurrected thanks to the disc, I tried to help them find it. Decades whirred by in weeks. Everyone aged quickly and one by one, turned to dust until only I was left.
Y/N: Okay, so what now?
M/N: You've got to change it back. Right up till the end, Velma said the Planispheric Disk could reverse the process. Where did you hide it, son? We have to get that Disk.
Y/N: I know where it is... I hope.
Y/N takes his mom to the Tiki Tub.
M/N: The Tiki Tub. It was hidden here the whole time?
Y/N: Yep. Come on.
Meanwhile with the others the gang arrives at the same location.
Fake Y/N: Everybody out.
Shaggy: Like, this is more like it. Ha, ha, ha! The Tiki Tub makes me, like, famished.
Scooby: Yeah, yeah, yeah.
Fake Y/N pulls them out.
Fake Y/N: What's wrong with you two? You're like bottomless pits. We're not here to indulge your munchies. We're here for that Planispheric Disk.
Daphne: Y/N, you're the one who hid it here. I don't understand why you don't know where it is.
Fake Y/N: Oh, you don't understand? Intellect isn't your strong suit, huh? What about you? Got any smarts in there behind those eye goggles?
With the real Y/N, M/N was looking everywhere.
M/N: Y/N, we've looked everywhere. It's not here.
Y/N: Hey, wait a minute. You're right. This wasn't the last place I hid the disk. The trip through the mirror must have jangled my memory. Now I remember.
In the real world, fake Y/N was with the gang.
Fake Y/N: Never mind, change of plans. This isn't where I left it after all.
Y/N takes his mom to the American Arcade.
The America Arcade? You hid the disk here?
Y/N: Sure. Come on.
With the others they were all looking around.
Fake Y/N: It's got to be here somewhere. Keep searching.
Shaggy: What's the score?
Fake Y/N: The score, Norbert, is that we're gonna find that disk tonight.
Fred: He means the score to the baseball game. That you're listening to. On those earbuds.
Fake Y/N: Heh. I knew that.
Velma: It's not Norbert. It's Norville. And nobody calls him that. It's always Shaggy.
Fake Y/N: I suggest less nitpicking and more searching. Wait. What? It's not here. Get back in the van.
Y/N takes his mom to P-P-Pizza Planet.
M/N: P-P-Pizza Planet. Scooby and Shaggy love it here.
Y/N: Exactly why I put the disk here.
The gang were looking around for the disk.
Velma: Y/N, this is all very bizarre.
Fake Y/N: You don't know the meaning of the word, child.
Y/N then sits up.
Y/N: I just remembered where I actually hid the disk.
Y/N takes M/N to Lover Lane, S-S-Sleeping Time building for mattress, the Strip Mall, No Tell Motel, and the freight at the docks.
Y/N: Here we are. This time for sure.
M/N: The freight? Why? It's so random.
Y/N: Exactly. No one will look here.
Meanwhile the others were on the freight looking.
Fake Y/N: I don't know. Look in all the desks, I guess. I'll check out the superintendent's office.
Velma: Gang, something is definitely wrong here. I mean, is it me or is Y/N acting stranger than usual?
Gang: It's not you.
Velma: Maybe if we can retrace our steps, we'll see a pattern.
She writes down all the places they have been.
Velma: Tiki Tub. American Arcade. P-P-Pizza Planet. S-S-Sleeping Time. Strip Mall. No Tell Motel. Freight's.
She circles a word.
TIki Tub
AMerican Arcade
P-P-Pizza Planet
LOver Lane
S-S-Sleeping Time
STrip Time
NO Tell Motel
FRieghrs
'IMPOSTER'
Daphne: Imposter?
Velma: I knew it.
Scooby: Then who is he?
Shaggy: And who sent the message?
Velma: My guess? The real Y/N.
Daphne: Wherever he is, he's probably in life-threatening peril. And in the clutches of some hideous creature.
With Y/N he was walking with his mom.
M/N: Where is it, Y/N? Where is it?
Y/N: Take it easy, mom. At least we now know it's not here.
M/N: You don't understand, son. We have to find that disk now. It's almost midnight. They'll be waking up soon.
Y/N: What? Who?
The skeletons begin to wake up.
M/N: The skeletons. The skeletons walk after midnight. Run!
Y/N grabs M/N's hand.
Y/N: Come on.
They run to the Mystery Machine, but it won't start.
Y/N: Come on, you hunk of junk, come on. Start.
M/N: Y/N! Y/N, they're coming.
The van starts as they drive off as the skeletons close in.
M/N: Y/N L/N, you remember every thing down to the smallest detail. Why can't you remember where you hid the most important relic in the universe?
Y/N: Wait, that's it. Now I remember. It's at the old abandoned factory.
Fake Y/N hears this.
Fake Y/N: Now that's more like it.
Shaggy: Should I just keep driving around in circles, Mr. Y/N, sir?
Fake Y/N: No, the old abandoned factory, hippie. And floor it.
Meanwhile Y/N was driving through the city.
M/N: This isn't the way to the factory.
Y/N: I know, we're going to the real factory.
Y/N drives to a wall.
M/N: Y/N, we're headed straight for that wall. It's solid brick.
Y/N: Is it, or is it?
Y/N rams through it breaking it.
Y/N: Fake. As fake as everything else in the old abandoned Crystal Cove movie studio. And as fake as you, mom.
M/N: How-How did you know?
Y/N: Easy, you messed up right at the start.
M/N: What?
Y/N: You said, jeepies, my mom has never in her life said jeepies. Once I knew you were fake, I figured Crystal Cove must be phony, too. It could only be the old movie studio made to look like a ruined town, complete with animatronics skeletons. Obviously, this was all about the location of the Planispheric Disk. Convincing me that I needed to save my friends from a post-apocalyptic future was the most obvious way to get me to tell you where I hid it. It's exactly what Fred would have done.
At the factory the gang arrives.
Fake Y/N: Fan out. Search every inch of this place until we find that disk.
Shaggy: Well, like, if you remember hiding it here, like, dude, where is it?
Fake Y/N: Well, the exact location slipped my mind.
He walks off.
Fred: We can't let that fake Y/N get his hands on the Planispheric Disk.
Scooby: What do we do?
Fred: We trap him.
Velma: Agreed. But it's got to be before he gets his hands on-
Fake Y/N: The Planispheric Disk. I found it! I found it!
Velma: Okay, never mind.
Daphne: Now that you've got it, what are you going to do with it? Fake Y/N.
Fake Y/N: Ahh, well done. You finally figured out I'm an imposter. So what? I'm taking the Planispheric Sisk, and who's going to stop me? You? You?
Y/N: No!
Y/N comes out of the shadows.
Y/N: Me... as in me, me. Whatever, you get the idea.
The two Y/N's fight over the disc as the gang watches.
Daphne: Don't just stand there, Shaggy. Get in there and help Y/N.
Shaggy: Which one?
Daphne: Uh, the good one. Be careful, Y/N. Don't hurt him.
They all see the old M/N.
Scooby: Y/N's mom, you look terrible. You should get more sleep.
Y/N pushes the second Y/N into a lever and lava pours towards the gang as they run. The two Y/N's continue to fight as Y/N 1 kicks him.
Y/N 1: I'll never give up this disk. You'll never beat me.
Y/N 2: I don't need to beat you. I just need you to stay put. Time to pull a Fred.
Y/N 2 throws a chain around his other self's leg and activates a magnet that pulls him up as Y/N 2 gets his foot stuck in a bucket and is pulled up as well. The gang runs over to the two Y/N's.
Y/N 1: Get me out of this. He's the fake.
Shaggy: They're, like, identical, right down to the shoes. Which one's the real Y/N?
Daphne: Allow me. Y/N, how do you feel about me?
Y/N 1: What do you mean? You're my love, Daphne. I'm crazy about you.
Daphne: And you?
Y/N 2: Well, from the past few months we've been together, you've made me into a better person, and I'm somewhat nervous about our wedding that is in a few months and since I have something planned afterwards... I revealed too much didn't I?
Daphne: Oh, Y/N. It's you!
Daphne kisses the real Y/N as Velma releases them.
Y/N 1: Well, if you're so smart, then who am I really?
Y/N 2: You're one of the most heartless criminals Mystery Inc. has ever faced. Aren't you, Brad Chiles?
Y/N pulls his skin.
Brad: Ow! It's not a mask, you imbecile. I had plastic surgery to look like you. You would have spotted a mask too quickly.
Fred: I don't know what you think you were doing. You're supposed to be my father. But how could you try to impersonate my friend when you know absolutely nothing about him?
Velma: If he's Brad, that makes you Fred's sneaky criminal mom, Judy.
Velma pulls her skin.
Judy: Ouch! Watch it. I had plastic surgery, too.
Velma: I know.
Shaggy: Brad Chiles and Judy Reeves? Heh, heh. But, like, why?
Scooby: Yeah. Why?
Brad: For the treasure. What else? It was the genius mind of Professor Pericles that thought up the whole plan. Wasn't it, Judy?
Judy: That's right, Brad. While we went under the knife, Professor Pericles had Mr. E arrange for the Crystal Cove studio to be changed into an exact replica of the town.
Brad: Except more end of the world-ish, obviously.
Velma: I hate to be the one to point this out, but that's just crazy.
Professor Pericles: Is it, Velma? Or is it so brilliant you cannot begin to fathom its true genius?
They see Professor Pericles.
Gang: Professor Pericles?
Y/N: You failed, you stupid parrot. You'll never get your filthy talons on this disk.
Professor Pericles: On the contrary, L/N. You are going to hand it over to me, along with my associates, Fred's dear parents...
Y/N: Or what?
Professor Pericles: Or else I will destroy the one thing you care about most.
Shaggy: Zoinks!
Professor Pericles robots grabs Daphne.
Daphne: Y/N!
Y/N: Fine. You win. Take it.
Professor Pericles: Excellent. Auf Wiedersehen, you beautiful kinder.
He takes the disc and flies off as the gang walk together.
Daphne: Y/N, I'm so sorry. Pericles got away with the disk because I got grabbed by robots.
Y/N: Don't worry, Daph. The important thing is that you're back safe and sound. And you look even more beautiful.
Scooby: Only now Pericles has the Planispheric Disk.
Pericles then takes the Planispheric Disk to a secret chamber and places it in a special location, causing the room to change.
Professor Pericles: I'm coming for you, master. I'm coming to set you free.