Halloween is near and Castle is thinking about dressing up as a space cowboy for his big costume party. Anyone else think Nathan Fillion could handle that role with a certain degree of serenity? But we digress, partially because we don't want to plug another franchise, but primarily because there's a mystery that needs solving.
Castle meets Beckett at a cemetery where they find the body of a young man stabbed through the heart with a stake. The victim even has fangs! They are able to ID the dead guy as Crow, his chosen name within the Vampire Fetish Community. His real name is Matthew Freeman. At Crow's apartment, they discover he was working on a graphic novel. His landlady mentions a girlfriend that Crow had argued with recently.
They locate the girl, the Vampire Mistress Vixen, who says they fought over another lover that Crow had taken - Daemon, a writer with whom Crow was working on the graphic novel. Daemon and Crow had been shadowing Morgan Lockerby, a former Coven member turned paranoid homeless man. Later, Beckett learns from Ryan that there's a print on the stake belonging to Lockerby.
The team finds Lockerby's lair which houses an empty coffin. From the ceiling, Lockerby drops down on Castle and bites him on the neck. Sucks to be a mystery writer hunting vampires these days. As Lockerby flails about, he falls into a beam of sunlight and his hands begin to blister! Lanie tells them that he suffers from porphyria, a disease that causes extreme photosensitivity, hallucinations, and paranoia. This is evident, as Lockerby spouts gibberish like "spots all over" and "I should've buried you then, wicked boy."
The team later finds Daemon, who has also been murdered, yet was killed before Crow. The killer apparently used one of the stakes found in his apartment. It couldn't have been Lockerby though, as Dameon was killed during the day. They discover an envelope taped to the bottom of a bureau containing articles about a murdered woman whose body was found two years ago. Castle and Beckett recognize the victim as the woman from Crow's drawings. But the sketches are dated two years before the body was found.
Beckett talks with Crow's family, Janice, Alan, and Rosie Freeman. No one recognizes the mystery woman in the sketches. Afterwards, Esposito lets Beckett know that the bullet wound the woman died from matches the 9 mm gun that killed Daemon. Ryan notices that the tree in one of Crow's drawings is identical to the tree where her body was found. Crow witnessed her murder 18 years ago, when he was just two years old.
The team discovers that Crow's father, Alan, changed his name from McGinty to Freeman (his second wife Janice's name) after the murder of his first wife, Elizabeth Dryden McGinty. Elizabeth IS the mystery woman. Castle recalls that the Dryden family crypt was near where Crow's body was found. They run through a theory where Crow realized that his father had been lying to him about who his mother was. Crow brought his father to his mother's grave to face the truth and that's where daddy dearest killed him.
Beckett and Castle confront Alan with this theory, but he explains that he didn't admit to recognizing Elizabeth's face because he didn't want to upset his daughter, Rosie. Beckett doesn't buy it and tells Alan that the Connecticut police just recovered a handgun from his house that's the same caliber as the one that killed Daemon and Elizabeth.
Heading out of interrogation, Castle recognizes that Janice Freeman is wearing a spotted leopard coat and connects it to "spots" - one of the phrases that Lockerby has been repeating over and over. Suddenly, another one of those phrases, "I should've buried you then, wicked boy," makes sense as well. Castle leads Janice Freeman past the holding cell where Lockerby waits. He screams at her, pointing her out as the murderer.
Janice killed Elizabeth so she could have Alan for herself. Crow had witnessed this crime as a little boy, but couldn't comprehend it. Haunted by the face of his real mother, he finally began to put the pieces together when Daemon showed him the article about his mother's body being found. Realizing that they were figuring out what she'd done, Janice killed Daemon first and then used the stake from Daemon's apartment to kill Crow. She tried to pin the blame on the vampire community.
At Castle's Halloween party, the big question is if Beckett will show up. She does, but doesn't seem to be wearing a costume. When Castle approaches her, Beckett opens her coat. Out pops an alien monster she attached to her belly, nearly scaring our favorite mystery writer to death. Happy Halloween!