
Neil Patrick Harris stars as Billy, A.K.A. Dr. Horrible, a budding super-villain whose plans for world domination continually go awry. His two goals: getting accepted into the Evil League of Evil, and working up the guts to speak to his laundromat crush Penny, played by Felicia Day. The only thing standing in his way is Captain Hammer, Billy's superhero arch-nemesis played by Nathan Fillion With one big score, Billy could get into the E.L.E. and earn the respect of Penny, but only if he can keep her away from the dashing Captain Hammer...

We are introduced to Dr. Horrible who tells us through musical numbers about his plan for world domination, his arch nemesis; Captain Hammer and his long-time crush on the girl from the laundromat; Penny. Penny also happens to be falling for Captain Hammer after he 'saves her life.'

After accidentally introducing Penny and Captain Hammer in the first place, Dr. Horrible is devastated that they seem pretty close. He concentrates on his freeze ray heist but after another setback, Bad Horse insists on a special demonstration of evil.

Bad Horse has insisted that only a murder will get Dr. Horrible into the Evil League of Evil, and now that Captain Hammer is dating Penny, his death seems to be the perfect choice. Will the prospective super-villain pull off his dastardly plan? And what will Penny think of him if he succeeds?
Complete episode guide for Dr. Horrible's Sing-Along Blog with detailed information about every season and episode including air dates, summaries, ratings, and streaming availability in United States.
This episode guide is organized by seasons, making it easy to track your viewing progress or find specific episodes. Use the episode information to plan your binge-watching sessions or catch up on missed episodes.