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.

Witness the birth of Tenacious D, the self-proclaimed greatest rock band of all time. On a fateful day on Venice beach, JB and KG meet and realize that they were destined to make history by combining their musical genius. But when overnight success eludes them, they set out to find the legendary "Pick of Destiny"--A special guitar pick believed to possess magical powers that can turn any open-mike wannabe into a rock legend.