The Templeton brothers — Tim and his Boss Baby little bro Ted — have become adults and drifted away from each other. But a new boss baby with a cutting-edge approach and a can-do attitude is about to bring them together again … and inspire a new family business.

A drug sniffing agent canine is a target for an assassin boss so the FBI calls Witness Protection to send him somewhere else. Meanwhile a single Mom puts her 6 year old boy James in the care of her irresponsible, mailman, neighbor, Gordon, when the babysitter bails on her. Meanwhile, an assassin mob boss hires 2 goons to kill Agent 11. But when 11 escapes from the van when they tried to kill him, he hides in Gordon’s Mailtruck that James is in too. And guess what they name him. Spot.