In the fourth episode of "Undead Girl Murder Farce," aptly titled "The Headliner Appears," Aya and Tsugaru set the stage for their theatrical "farce" to expose the murderer. As part of the opening ceremony, they use traditional wooden clappers.

The episode focuses on Raoul, a character hinted at as a potential culprit in earlier episodes. He is often portrayed as distant from his brother Claude and sister Charlotte. This depiction contrasts with his siblings, who are frequently shown in the company of their patrons.

Aya begins unraveling the mystery of the murder. She uses a dollhouse, previously featured in the series, as a tool to illustrate her theories. As Aya solves the puzzle, the scene is overlaid with Charlotte's haunting singing, foreshadowing the imminent resolution of the murder case.

The narrative takes an unexpected turn when Aya reveals a crucial piece of evidence. The ensuing scenes provide further clues pointing to Raoul as the murderer, with the visuals emphasizing his nervous behavior and avoidance of direct eye contact. A red outline underscores Raoul's status as the prime suspect. The episode reaches a pivotal moment when Aya publicly accuses Raoul of the murder, provoking an aggressive reaction from Raoul, who attacks Tsugaru.

A fierce battle ensues between Raoul and Tsugaru. Their contrasting fighting styles are highlighted, accentuated by Tsugaru's confident self-assurance. During this fight, Tsugaru's past as a member of a yokai extermination group in Japan is revealed.

In the episode's closing scenes, Raoul appears defeated. Aya, Tsugaru, and Shizuku subsequently leave the manor, seemingly bringing the mystery to an end.