The town of Smallville prepares for its annual music festival, but a mysterious songstress starts using her music to manipulate the townspeople. Clark must stop her before it's too late.

Season 3 is widely regarded by fans as one of the darkest seasons of the series, focusing on Lex Luthor's mental breakdown and Clark's internal struggle with his Kryptonian destiny .

The finale of Smallville Season 3 changes everything. Jor-El gives Clark an ultimatum: abandon your human life or watch everyone you love die. In the final scene, Clark is struck by a lightning bolt from the Fortress, and his powers vanish. Simultaneously, a mysterious young woman (a fake Kara) arrives, burning the "S" shield into the Kent field, warning that Clark has failed.