The storyline starts in 1996. A young, CG-enhanced version of Dwayne Johnson plays overweight and geeky misfit Robbie Weirdicht, the frequent target of ridicule by the bullies in his high school. By contrast, the most popular kid in school, Calvin Joyner, is the kind of most-likely-to-succeed guy who excels in school in all the ways Robbie does not, but bestows an act of kindness on the pudgy kid during a particularly humiliating prank that exposes him, clothesless, in front of his entire student class at an assembly. Fast-forward to today, approaching the day of their 20th high school reunion, and mid-level accountant Calvin, who feels he peaked in his teenage years, is adamant that he will not go, protesting to his wife, his high school sweetheart, that he can't face up to feeling like a disappointment. She suggests a marriage counselor to work all this out.
That's when Calvin gets a Facebook friend request from out of the blue by someone he thinks is a stranger named Bob, but ends up being Robbie, now a hunk, rippling with muscles, even though he seems the same goofy kid inside, and who has spent two decades idolizing the closest thing he ever felt to having a friend due to one small, selfless act (the movie hints at but stops just short of replicating The D-Train in this regard). The two catch up on old times, but Calvin is soon confused with being Bob's friend by CIA agents looking to arrest him, accusing him going rogue from their agency and in secretly being the notorious international criminal known as the Black Badger, looking to sell top-secret information regarding U.S. government satellites to bad guys.