At the heart of the episode is the intense rivalry between Lupin and Holmes as they compete for possession of the Penultimate Night, a valuable object. Lupin attempts to outwit Holmes by disguising himself. However, an attentive viewer might recognize Lupin's identity through a small detail: his shoes.

Holmes, not one to be easily outmaneuvered, retrieves the Penultimate Night from the safe and hides it with another person for safekeeping. Lupin, however, reclaims the Penultimate Night using a smoke bomb, seemingly gaining the upper hand in their contest.

Just as Lupin is about to make his escape, Tsugaru interrupts him with a historical tale about Goemon Ishikawa, which delves into the origins of the smoke bomb in Japan.

In a comedic twist, Aya Rindo enters the scene and unexpectedly hits Lupin with the door of the safe around which they had devised their strategy, adding a humorous layer to the episode.

Tsugaru's interrupted story about Goemon Ishikawa returns as a crucial plot point. A flashback reveals that Lupin made a critical mistake: he had overlooked an important detail about Aya, leading him to underestimate both her and Tsugaru.

The story takes a significant turn with the introduction of Moriarty's group, a collection of unique characters: Aleister Crowley, a renowned illusionist; Carmilla, a vampire with a particular preference; Victor, who may allude to Victor Frankenstein; and the enigmatic Jack.

Amid the ongoing tensions, Royce, Lupin, and Tsugaru are drawn into a confrontation, as they all have their eyes on the Penultimate Night. Meanwhile, Holmes and Watson, ever vigilant, intervene and engage in a remarkable stalemate with Crowley. Holmes' quick thinking prevents an assassination attempt on Watson and thwarts Crowley's poisonous plan.

Carmilla's dominance becomes evident as she joins the fray, with hints that Shizuku is being set up as her rival.

The episode reaches its climax with an exhilarating aerial battle between Royce, Lupin, and Tsugaru. In a thrilling finale, the Penultimate Night lands in an inaccessible location—the chapel's pulpit—leaving the outcome of the treasure hunt hanging in the balance.