"Dead Mount Death Play - Episode 19" begins with Inspector Tsubaki Iwanome and his team, which includes Yatsu and Pops, reflecting on the aftermath of their recent operations. They discuss the media interest in the Habaki case and the potential risks to Iwanome's safety, deciding to proceed cautiously given the unknown scale and strength of the organization they are dealing with.

In a flashback, a conversation between Polka and a mysterious being from another world, referred to as "Your Imperial Majesty," is shown.

Polka confronts Izliz and prevents him from committing an act of violence. Polka's interactions with various characters, including Clarissa and Takumi, are highlighted.

The climax of the episode is the confrontation between Polka and Xiaoyu. Polka challenges Xiaoyu to a serious battle, testing his abilities and revealing the extent of his own powers. This encounter leads Polka to propose an alliance with Xiaoyu, offering him a powerful new weapon in exchange for his cooperation.