Dr. Horrible's Sing-Along Blog
Dr. Horrible's Sing-Along Blog consists of three acts of approximately 14 minutes each. They were first released online in July 2008 as individual episodes, with two-day intervals between each release.
=== Act I ===
Dr. Horrible is filming an entry for his video blog, giving updates on his schemes and responding to various emails from his viewers. Asked about the "her" that he often mentions, he launches into a song about Penny, the girl he likes from the laundromat ("My Freeze Ray").
The song is cut short by his "evil moisture buddy" Moist, who brings up a letter from Bad Horse, the leader of the Evil League of Evil. The letter informs Dr. Horrible that his application for entry into the League will be evaluated, and that they will be watching for his next heinous crime ("Bad Horse Chorus").
The following day, Horrible prepares to steal a case of wonderflonium for his time-stopping Freeze Ray by commandeering the courier van using a remote control device. Penny happens to be on the same street ("Caring Hands"), and appears asking him to sign a petition to turn a condemned city building into a homeless shelter. However, the remote requires his attention, and he appears uninterested in her and her cause. As Penny leaves, Horrible is conflicted, but opts to steal the wonderflonium, telling himself that 'A man's gotta do what a man's gotta do' ("A Man's Gotta Do").
When Horrible remotely drives the van away, Captain Hammer appears and takes over Horrible's song, smashing the remote control receiver and inadvertently causing the van to veer towards Penny. Hammer pushes her out of the way (into a pile of garbage) just as Horrible regains control of the van and stops it, making it appear that Captain Hammer stopped the van with his bare hands. The two confront each other, with Hammer slamming Horrible's head on the van's hood, but Penny emerges to thank Hammer, making him forget about beating up Dr. Horrible. As Hammer and Penny serenade each other, Horrible glares at them while he makes off with the wonderflonium.
=== Act II ===
Dr. Horrible stalks Penny and Captain Hammer on their dates; Horrible sings of the misery of the human condition, and Penny sings of hope and the possibility of redemption ("My Eyes"). Penny and Horrible, known to her as Billy, begin to talk openly as friends.
On his blog, Horrible reveals that his Freeze Ray has been completed, and that he plans to use it the next day. The following post reveals that he has failed, as Hammer and the LAPD watch his blog, and they were ready for him. He then receives a phone call from Bad Horse and is reprimanded, saying that the only way to be inducted now is to commit an assassination ("Bad Horse Chorus (Reprise)"). Horrible is conflicted and can't decide on a victim, or even if he wants to commit a murder at all, even though the League will deny his application if he doesn't.
Billy chats with Penny over frozen yogurt, at the laundromat, about his problems ("Penny's Song"). As they grow closer, Penny mentions that Captain Hammer is planning to drop by. Billy panics and tries to leave, only to run into Hammer as he walks in. They feign ignorance on recognizing each other, but when Penny leaves them alone, Hammer reveals that he recognizes Billy as Dr. Horrible. Captain Hammer then taunts Dr. Horrible about his crush on Penny, happy to be taking the thing that Dr. Horrible wants most. It becomes obvious that Hammer doesn't really care about Penny but just wants to sleep with her to spite Horrible. Horrible decides to kill Hammer as his heinous crime for admission to Bad Horse's Evil League of Evil ("Brand New Day").
=== Act III ===
The city is abuzz with Captain Hammer's crusade to help the homeless and he is considered the city's new hero; Penny ponders her relationship with Captain Hammer, waiting at the laundromat to share frozen yogurt with an absent Billy; and Dr. Horrible goes into seclusion while obsessively constructing a Death Ray to kill Captain Hammer once and for all ("So They Say").
At the opening for the new homeless shelter, where a statue of Captain Hammer will be unveiled, Captain Hammer begins a speech of encouragement to the homeless, but it degenerates into self-centered, condescending praise of his own excellence and relationship with Penny ("Everyone's a Hero"). Penny, embarrassed and disillusioned, quietly tries to leave as the crowd joins in singing Hammer's song, but they are interrupted by the appearance of Dr. Horrible, who uses the Freeze Ray on Captain Hammer, cutting his song short. Dr. Horrible taunts the shocked crowd and declares that they cannot recognize that Hammer's disguise is "slipping", and he reveals a second, more lethal laser gun: his completed Death Ray ("Slipping").
At last, Horrible aims the lethal weapon at the frozen form of Captain Hammer, but hesitates. At that moment the Freeze Ray unexpectedly fails, and a suddenly revived Hammer punches Horrible across the room. The Death Ray falls from his hands, damaging it. Hammer then picks up the Death Ray, turns it on Horrible, and triumphantly completes the final note of his prior song. However, ignoring Dr. Horrible's warnings, Hammer pulls the trigger and the damaged Death Ray misfires. The weapon explodes in Hammer's hands, injuring him and causing him to feel pain, apparently for the first time in his life. He flees, a wailing wreck, asking for "someone maternal". Dr. Horrible realizes suddenly that he has succeeded in vanquishing his nemesis, but still having not committed the murder required by the League. Unfortunately, he discovers Penny slumped against a wall, impaled by shrapnel from the exploding weapon. Tragically, she dies in Horrible's arms, deliriously reassuring him that Captain Hammer will save them.
Dr. Horrible declares a Pyrrhic victory, with "the world [he] wanted, at [his] feet", seeing that her death is ironically the murder he required. In the aftermath, Horrible gains infamy and is free to commit additional crimes unfettered by Captain Hammer. Horrible becomes a member of the League, striding into a party in celebration of his induction, attended by Moist and the villains Pink Pummeller and Purple Pimp. Meanwhile, Captain Hammer is seen on a psychiatric couch sobbing to his therapist.
Dr. Horrible, donning a new outfit – red coat, black gloves and his goggles covering his eyes – takes his seat at the League, composed of fellow super-villains Tie-Die, Snake Bite, Professor Normal, Dead Bowie, Fake Thomas Jefferson, Fury Leika, and Bad Horse (who proves to be an actual horse). He addresses the camera, saying, "now the nightmare's real", and in working "to make the whole world kneel", that "[He] won't feel...". He completes the line "...a thing" in a final blog post as Billy, out of costume, looking numb and lost in the midst of his lab. ("Everything You Ever")
romantic, comedy, entertaining