"Dark Gathering - Episode 22" begins in the midst of a confrontation where Otogiri engages in a fierce battle against a ghost boy. Despite the ghost boy's brave efforts, Otogiri emerges victorious. Yayoi and Keitaro then work together to reseal Otogiri using the help of the Castle H ghost and the tools that were used to seal the high priest.

A pivotal moment arrives when Yayoi confronts the ghost boy, acknowledges his pain, and offers a compromise to soothe his anger. She seals him inside a lion plush toy and compassionately returns his sketchbook to him. This act of understanding highlights Yayoi's unique approach to dealing with spirits.

The plot intensifies when Keitaro discovers Shami’s bag, which contains the other half of a cursed mummy arm relic. This discovery raises questions about Shami’s involvement and whereabouts. Despite searching, they cannot find Shami’s ghost, leading Yayoi to suspect that he is being controlled by another spirit.

After calling the police, the trio is taken to the police station with the relic. There, they meet Namiko, Shami’s sister, who blames them for Shami’s death. Namiko reveals her own spirit-seeing abilities and, in a shocking revelation, discloses that Shami—or Nagiko—has been replaced by a ghost. She offers to train Yayoi, but Yayoi refuses. However, this interaction deepens the mystery surrounding the spirits' influence.

Namiko’s knowledge of how to detect spirit possession proves valuable, and she vows revenge against the spirits for her sister’s fate.