探偵・癸生川凌介事件譚「死者の楽園」

This case is a few months after the nightmare of "The Kairoukan Murder Case", the second in the series. The story begins with a visit to his friend, Kibukawa, who is in need of a new story.
At the office after a long absence, a beautiful secretary "Haruna Kikukawa", who works at the popular amusement park "Shangri-La," comes to consult.

The request was for security and investigation into a cult-like threatening letter sent to the amusement park and a spooky prank. However, Hiroshi Kimijima, the president of the company, wants the matter handled confidentially without informing the police. Despite their disbelief, Ikuo and Itazura head for Shangri-La.