The Keba family was organized by the group leader Shishi to go to Xi'an Island for fun. Everyone who came to Xi'an Island received a threatening letter from Madao.
Is a family's home really still a home? What exactly happened three years ago?
Friends who died one after another, frivolous and careless girls, unknown organisms, straightforward children...
The ending, what will it be?
[This is a novella about Ke Ba and his family's detective adventure. The characters' personalities have been destroyed and darkened in various ways.