Neil Patrick Harris (How I Met Your Mother) 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 Guild). The only thing standing in his way is Captain Hammer, Billy's superhero arch-nemesis played by Nathan Fillion (Firefly). 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...
Conceived as an "online miniseries event" during the 2008 writers' strike, Dr. Horrible's Sing-Along Blog is a 42-minute musical romp that bears the distinctive stamp of Joss Whedon. Neil Patrick Harris (How I Met Your Mother) plays the title character, who video-blogs about his twin goals to join the Evil League of Evil and to woo the fair Penny (Felicia Day, of Whedon's Buffy the Vampire Slayer and the Web series The Guild), a woman he met at the local laundromat. Dr. Horrible is foiled on both fronts, however, by his arch-nemesis, the self-absorbed superhero Captain Hammer (Nathan Fillion, Whedon's Firefly).