Gru meets his long-lost charming, cheerful, and more successful twin brother Dru who wants to team up with him for one last criminal heist.
After he is fired from the Anti-Villain League for failing to take down the latest bad guy to threaten humanity, Gru finds himself in the midst of a major identity crisis. But when a mysterious stranger shows up to inform Gru that he has a long-lost twin brother-a brother who desperately wishes to follow in his twin's despicable footsteps-one former super-villain will rediscover just how good it feels to be bad.
Balthazar Bratt, a child star from the 1980s, rises to power and wants world domination. As Gru and Lucy Wilde attempt to stop him from stealing the largest diamond in the world, they fail as he flies away. Gru and Lucy are fired by Valerie Da Vinci from the AVL, and are jobless. As Agnes tries to sell things to get money, Gru receives news he has a twin brother. He flies to Dru's location, but finds out he is a more successful and rich super villain. Dru wants Gru to team up for one more heist, which he gives in to. Without Lucy knowing, they plan to steal the largest diamond in the world from Bratt, as the Minions get themselves in prison.