1x15 - The Wallflower

Sunako and the others are invited to an island that has a history of pirates burying treasure there. Kyohei sets off to find treasure, while Sunako looks for skeletons. Then when Sunako finally finds what she's looking for, it starts to cause trouble for the guys. It is revealed that she is possessed by a spirit who activates traps sets throughout the island. Noi eventually arrives at the island, worried about Takenaga. However, the spirit causes the Yuki, Ranmaru, Takenaga, and Noi to hallucinate, being possessed in the process, while Kyohei encounters the possessed Sunako. Sunako is about to release the spirit due to her love of the skeletons, returning everyone back to normal.