Colin Farrell is riding to his house on a motor scooter, carrying several boxes of jelly donuts. He has gotten really fat since the events of Phone Booth I, and now he only leaves the house to get food. He drives past an alley and hears a woman screaming for help. Hesitantly, Colin stops his scooter and peeks around the corner, and witnesses a gang member about to rape the woman. Colin throws a donut at the rapist and then Rapey gets scared and runs away. But he's already stabbed the woman in the arm so she needs medical assistance. Colin takes out his mobile phone to call 911, but he can't get a signal in that area. But there is a phone booth right next to the alley. Colin could either use that phone booth, or let the innocent woman die. Colin starts crying, "Sorry, lady, I can't do it" and speeds away. Cut to later, Colin is sitting on his bed naked, eating donut after donut, and watching the news. That woman in the alley died, and now police are on the lookout for a fat donut-eating fuck on a scooter, who was witnessed crying and eating donuts at the scene.
Fat Colin Farrell rides his scooter down the police station to turn himself in, and he is arrested and sent to prison. The prison guard is like "Okay, tubby, here's your cellmate... this guy's a real sick fuck, just like you." and the cellmate turns around to reveal that he is Kiefer Sutherland, the infamous Phone Booth Killer. Kiefer's like "I call top bunk" and Colin starts screaming. Kiefer calms him down, explaining that his Phone Booth Killing days are over, and that he confessed his crimes so that he could turn over a new leaf. Then he gives Colin a donut. Later that night, Colin wakes up and sees Kiefer digging a hole in the wall with a spoon. During the day, the hole is covered by a poster of Zac Efron. Colin's like "What the fuck are you doing, Keefs" and Kiefer quickly puts his hand over Colin's mouth and holds the spoon to his throat. "I'm escaping, lardo. I've been planning this for months, and you're the final part of the plan..." Colin doesn't understand, and Kiefer's like "Remember that donut you ate earlier?" We see a flashback to when he gave him the donut, and a close-up reveals that it's not really a donut at all, it's a piece of the prison cell wall, covered in sprinkles. Kiefer is going to escape by digging away the wall and feeding the pieces to Colin Farrel so the guards won't suspect a thing.
The next day in the lunch line, some guy tries to shiv Colin Farrell because his morbid obesity offends him. But Kiefer defends Colin by blocking the dude's shiv with a lunch tray and then decapitating him. Then he takes that dude's lunch and gives it to Colin, so now Colin has two lunches. Colin is like "Thanks, man." "No problem, pal," says Kiefer, "Just make sure you save room for that cement wall I'm digging out later tonight." The Prison Snitch overhears this, and runs to tell the Warden. The Warden is like "That's fucking stupid" and puts the snitch in The Hole for lying. Later that night, Kiefer Sutherland is romantically feeding Colin Farrell pieces of the cell wall. Then they hear a guard coming, so Kiefer's like "Quick, pretend we're making out" so they start making out and the guard sees them and is like "Yep, nothing suspicious going on here." After the guard leaves, Kiefer's like "Your breath tastes like cement, you disgusting fat piece of shit."
The following morning, Kiefer and Colin wake up after a night of hot, steamy lovemaking. Colin is lying on top of Kiefer and he's like "I see now why they call you the Phone Booth Killer. And by 'Phone' I mean 'Fat' and by 'Booth' I mean 'Cock' and by 'Killer' I mean 'Sucker'." Kiefer doesn't respond. Colin continues talking, "Anyways, I'm almost done eating that wall, so tonight we escape, buddy." Kiefer still says nothing, and that's when Colin realizes that he tragically crushed him to death under his fat, cement-filled body. Colin's like "Noooooooooo" and crawls into the hole in the wall and eats the rest of the way out. He then waddles his way to the prison fence and starts climbing it. But the fence is electrified, and it fries the shit out of Colin, causing him to explode. Pieces of blubber and cement rain down all over the prison, killing dozens of innocent prisoners. Later, a doctor is doing an autopsy of Kiefer Sutherand. His finishes up his report, "If only the fat guy didn't eat all that cement, these two homos could've fucked all night long and lived happily ever after."