Gru delights in all things wicked and vanquishes all who stand in his way until he encounters three little orphaned girls who look at him and see something that no one else has ever seen: a potential dad.

When his band votes him out due to his embarrasing musical antics, Dewey has to make the rent somehow. After intercepting a call for his substitute-teacher roomie Ned, Dewey finds himself in front of a class of elite elementary school students. Dewey decides to take on the music program and makes it his goal to teach them the gospel of rock and roll. His ulterior motive is to get them to compete against his former band for a cash prize.