Bob Stone (Dwayne Johnson) is a former high school loser who went from being a morbidly obese teen with a horribly funny name to being a muscular CIA agent with a new identity. But when he was a senior in high school, five bullies teamed up on him while he danced and sang while naked in a gym shower, and dragged him into a gym packed with classmates before dumping him to be humiliated in front of everyone. The only student who wouldn't laugh at him was the school's star student, Calvin Joyner (Kevin Hart), who gave him his letterman's jacket to cover his implied naked genitals and walk out with some dignity.
Twenty years later, now known as Bob and musclebound, the loser victim finds Calvin while in town for their reunion. Calvin has gone from star to average-joe accountant, and he now feels disappointed in his life, but Bob finds him on Facebook and asks him to meet night before reunion for drinks to talk. Then, he invites his way into staying overnight in Calvin's house.
The next morning, Calvin is shocked to find three CIA agents at his door, looking for Bob. Bob disappears instantly though, but quickly returns to drag Calvin into a crazy set of misadventures as they try to figure out who a secret villain named the Black Badger is in time to prevent him from selling a chip with government secrets on it in an online auction to enemy nations.
Bob needs Calvin's accounting expertise to track down where the bank accounts of the bidders are located and find the winner to arrest him. But the three agents claim that it is Bob who went crazy and turned traitor, and is the one selling the secrets himself. Calvin is asked by them to report if Bob contacts him, but within moments Bob has swooped back to get him, Calvin is convinced Bob is telling the truth and the two go on the run from the feds while hoping to arrest the auction winner and reclaim the files.
