After two films of true friendship and relentless flirting, Poppy (Anna Kendrick) and Branch (Justin Timberlake) are now officially, finally, a couple – but as they grow closer, Poppy discovers that Branch has a secret past. He was once part of her favourite boyband phenomenon BroZone, with his four brothers, but BroZone disbanded when Branch was still a baby, as did the family, and Branch hasn’t seen his brothers since. But when Branch’s bro Floyd is kidnapped for his musical talents by a pair of nefarious pop-star villains, Branch and Poppy embark on a harrowing and emotional journey to reunite the other brothers and rescue Floyd from a fate even worse than pop-culture obscurity.