Dr. Horrible's Sing-Along Blog is a 2008 musical comedy-drama miniseries in three acts, produced exclusively for Internet distribution. Filmed and set in Los Angeles, the show tells the story of Dr. Horrible, an aspiring supervillain; Captain Hammer, his superheroic nemesis; and Penny, a charity worker and their shared love interest.

Mutant Enemy Productions is a production company that was created in 1996 by Joss Whedon to produce Buffy the Vampire Slayer. The company also produced the Buffy spin-off, Angel, and his two short-lived science fiction series, the space Western Firefly and his high-concept Dollhouse, produced by 20th Century Fox Television. Mutant Enemy also produced the internet series Dr. Horrible's Sing-Along Blog and the film The Cabin in the Woods. Mutant Enemy produced the superhero series Agents of S.H.I.E.L.D. along with ABC Studios and Marvel Television. Most recently, Mutant Enemy produced the supernatural fiction series The Nevers for HBO.