General warning for the Dursleys being their wonderful selves, so definitely abuse. If anything triggers you, a summary will be in the end notes.
Harry groaned and rolled over, hitting a wall. He muttered under his breath and rolled the other way, only to hit another wall. He was instantly awake, trying to sit up, only to almost scream in pain. He bit his lip to hold it in and gingerly sat up, bracing himself against the wall to help. He winced as he felt the wounds on his back stretch and open again, letting the blood soak even more through his shirt. A few minutes later he heard Aunt Petunia coming down the stairs.
"Get up!" she hissed, rapping on his door and unlocking it. "Vernon wants his breakfast, and Dudley's coming home today, so dinner had best be perfect!"
Harry groaned internally and managed to force himself out of the cupboard. He got to the kitchen and began making eggs, bacon, and toast. If Dudley was coming home today, he must have been unconscious for at least a whole day. Unfortunately, Harry knew well enough how that felt, so he just quickly got back into the swing of the morning. He finished putting a huge smear of butter on the toast just as Uncle Vernon began stomping down the stairs and he quickly plated the food, putting it and a cup of coffee at Uncle Vernon's usual seat. Then he began doing the dishes. They took a little longer than usual since he was favoring his back a bit, but they were done before Uncle Vernon stomped over to Aunt Petunia for his usual morning kiss before heading off to work. Harry grabbed his uncle's dishes and glanced to his aunt to see if she was going to eat. She continued to sip her tea, so Harry finished with the plate and utensils and went to stand quietly next to Aunt Petunia.
"You'll be in the garden today. I want the tulips sorted by color, all the weeds pulled, the roses sorted by size, large ones in front, and I want you to plant the azaleas I bought yesterday. After lunch, which you may or may not get depending on how well you do in the garden, you'll be doing other outside things."
"What order do you want the tulips in?" Harry asked quietly.
"Red towards the front of the house, followed by pink, yellow, and white. Get to it!" she snapped.
Harry quickly went outside to fix the garden to her demanding standards. Padfoot bounded over as soon as he saw Harry, whining frantically, and Harry smiled down at the dog.
"Come on, Padfoot, let's go work in the garden. Aunt Petunia gave me quite the list." He continued rambling as they made their way to the garden, Padfoot prancing around, acting like the dog he was to cheer his godson up. When Harry knelt down in the dirt to begin weeding, Padfoot flopped down next to him, transforming back into his human form.
"I'm sorry, pup. I shouldn't have come in those nights. I'm not going to do it again. I'll sleep in the shed."
"Padfoot, it's fine. I just didn't wake up early enough."
"No, Harry. I'm not going to stay with you at night while we're here. I'm not going to be the reason you get a beating so bad you sleep for a whole day ever again. I know I can't stop those monsters if they hurt you, but I'm never going to be the reason for it again." He grabbed a few weeds while he spoke, putting them in the pile with Harry's.
Harry was silent for a minute, then he changed the topic. "Any idea why Professor Dumbledore was so interested in the note? We know You-Know-Who is alive. He was there both my first and second years."
Sirius growled a little bit at the reminder, then sighed. "The handwriting looked like my brother's."
"Regulus?" Harry asked curiously.
"Yeah. Reg disappeared in the last war at some point. We were never sure which side killed him. No one claimed it. There were a lot of deaths like that, especially near the end. Good ole Voldy was getting paranoid and sometimes killing off his own people. Dumbledore tried to keep us from killing people, but a bunch of us were Auror trained, and it was a war. If we're just using Stupefy and Expelliarmus while they're using Avada Kedavra and Crucio you can tell pretty quick who's going to win. We quickly started using cutting curses aimed at the neck, levitating charms on rocks and boulders to drop on our opponents, and several others. Some of our spies were able to sneak poisons into drinks undetected, or they had to poison themselves, and the other side's spies did the same. It was chaos, and no one truly knows how many died. Did you know, a Ferula aimed at the neck and face will smother someone in minutes? A slow death, but it's just the bandaging charm. You use it to splint broken limbs in an emergency."
Harry was silent as he moved on to rearranging the tulips. He pulled them up gently, one at a time, making sure to get all of the roots, then replanted them in a different spot. Finally he spoke. "I'm sorry about Regulus." He was silent for another moment, then asked, "Is there a charm to copy handwriting?"
Sirius didn't answer for a moment. "Ye-," he coughed and started again, "Yeah. There's a few. But the person has to have a sample of the handwriting for all the charms I know of."
Harry nodded, then dropped the subject. Sirius was thinking too much about the war, and Harry wasn't going to let that stand. "You know, the day that note came was the deadline for us to give you our answer about becoming Animagi."
Sirius nodded, relaxing into the grass. "Did you lot decide?"
"We want to accept. It's too much of an advantage to just brush off, and if we're Animagi without people knowing, then we have more ways of escaping anything that might happen to us." Harry sighed. "I guess we can't really do it this summer though, since you and I are stuck here. Would it be difficult to do during the school year?"
"I don't think it would be too hard, the worst part would be finding excuses to not speak for a month."
"If nothing else we can make a huge deal out of it. Maybe a bet, or one of us starting the Quiet Game, or Hermione declaring that she wants to try to learn sign language and wordless casting, and that the fastest way to do it would be not talking for a month or something. It wouldn't be that difficult." As he spoke, Harry moved on to rearranging the roses.
Sirius laughed quietly. "I can see why you were Sorted into Slytherin, Pup. You definitely have cunning in spades."
Harry grinned at the compliment and dropped an extra weed he found on Sirius' face, causing the adult to splutter and rub his face dramatically. Harry laughed and finished up the roses, quietly talking with Sirius about random things.
Harry finally stood up and wiped his trousers as clean as he could while Sirius transformed back into Padfoot, grabbing the sack of weeds to dump. Harry then hooked the hose to the spigot and quickly watered the garden before hosing off his hands and heading inside for whatever his aunt was going to give him for lunch. After eating the five carrot sticks she basically threw at him, she sent him outside to paint the shed and wash Padfoot, since "I will not have that mangy mutt be dirty near my house!"
Harry took one look at Padfoot, shook his head, and went to paint the shed. After he finished he grabbed the hose and looked over at Padfoot.
"Aunt Petunia demands you be washed, so are you going to be a good godfather and sit still or are you going to pretend to be the dog you currently are and try to run away?" he asked with a raised eyebrow.
Padfoot barked and bounded over to Harry. Harry grinned. "Guess that's a no on the running away then. You going to sit still?" Padfoot flopped down at his feet and rolled over, and Harry laughed, turning the hose on and pointing it at the dog. Padfoot instantly yelped at the cold water, jumping up and shaking vigorously to try to dislodge the water. Harry kept spraying him with the water, laughing as Padfoot tried to get away without running off. He finally shut the water off and began scrubbing the dog with one of the old towels Aunt Petunia refused to touch and some soap Harry had nicked from Uncle Vernon's shampoo bottle. After the thorough washing, he rinsed Padfoot off, then let him shake out all over the grass. Harry then used the other old towel he'd grabbed to rub Padfoot dry, just to have him shake water all over Harry before he even got close with the towel. Harry just laughed and grabbed the dog by the scruff and rubbed him dry before hosing himself down and drying off as best he could without getting any of Sirius' fur on him. Aunt Petunia might actually kill him if he brought dog fur into the house, especially on the day her precious Duddykins was set to arrive. That thought sobered Harry and he quickly headed inside, knowing Aunt Petunia would want him to make dinner to her exacting standards.
Petunia pointed towards the bathroom without even looking at him, so he quickly rinsed off in the shower and changed clothes, knowing she wouldn't want him in the bathroom for more than five minutes. He came back to the kitchen, where Aunt Petunia merely pointed at the stove, where Harry found a recipe for what he remembered was Dudley's favorite meal when they were younger.
An hour later found Harry setting the table for three and Uncle Vernon's car pulling into the driveway. Harry quickly put the last dish on the table, then hurried into the kitchen to wash the first of the dishes while the Dursleys ate. When he reappeared to take the dishes that the Dursleys were done with, Dudley spoke up.
"Dad warned me you were here, freak, but I was really hoping he was kidding. At least I get to practice my boxing skills and use my Smeltings stick for something useful this summer."
Harry ignored him and continued taking the dishes away. Thankfully Dudley didn't have the stick with him, or he was sure he would have been hit by now. After they finished dessert, Harry finished cleaning the kitchen and table, then headed towards his cupboard. Dudley, unsurprisingly, was leaning against the front door, holding his Smeltings stick and tapping it against the side of the house. Harry jumped lightly over it as Dudley swung it towards him, but Padfoot growled fiercely from the darkness outside. Dudley glanced fearfully outside for a moment, but when no other sound came, he smirked and swung at Harry again. Harry wasn't paying attention this time, and Dudley caught him on his barely healed back.
Harry bit his lip to hold back his groan and heard Padfoot's growling increase. He turned around just in time to see Padfoot leap from the darkness just outside the door into the light, causing Dudley to let out a high pitched squeal. Padfoot grabbed the stick and yanked it out of Dudley's hands, growling the whole time, then dropped it and snapped at Dudley's leg, missing by almost an entire foot. It seemed Padfoot was still thinking at least somewhat clearly, thankfully, but Harry knew this would still most likely end in a beating for him.
Surprisingly enough, it didn't, and Harry was just locked in the cupboard for the night with no meals for two weeks.
Two weeks later, Marge arrived.
Harry wakes up a day after the end of last chapter, and is forced to do outside chores all day with only a small break in the middle. He and Sirius are able to have a conversation, and at the end Dudley arrives.