Continuing the story of Max and his pet friends, following their secret lives after their owners leave them for work or school each day.

Former villain Gru (Steve Carell) is now an agent for the Anti-Villain League (AVL). He and his partner and new wife Lucy (Kristen Wiig) are sent to foil the plans of Balthazar Bratt (Trey Parker), a former child actor from the 1980s who has turned evil. Gru manages to stop Bratt from stealing the Dumont Diamond, a giant pink diamond, but is unable to capture him. As a result of failing to capture Bratt, Gru and Lucy are fired from the AVL by its unreasonable new Director Valerie Da Vinci (Jenny Slate), following the retirement of the AVL's former Director, Silas Ramsbottom (Steve Coogan).