Dr. Horrible, an aspiring supervillain with his own video blog, is attempting to join the prestigious Evil League of Evil (led by the legendary "thoroughbred of sin", Bad Horse), but his plans are usually foiled by the egotistical superhero Captain Hammer. Dr. Horrible's life is thrown for a loop when he falls in love with Penny, a bea...

After a bad breakup with his girlfriend leaves him heartbroken, Carter Webb moves to Michigan to take care of his ailing grandmother. Once there, he gets mixed up in the lives of the mother and daughters who live across the street.

Cast and crew of Dr. Horrible's Sing-Along Blog perform a musical commentary track as exaggerated versions of themselves.