Hello, I saw you again. I'm Ikurumi, a game scenario writer.

Do you know the previous work "Masque of Fantasy Murder Case"? Half a year since that incident. This time, it's called "Kairokan" It happened in a strange building built in the middle of the sea. Let me introduce the case.

The mansion built by the former chairman of a famous construction company. The story begins when you are invited to the inauguration event. 7 invited guests who visited. The master doesn't show up.
And a strange building that encompasses everything. What kind of events will be held?

And the incident happens.

A serial murder that occurs in a closed building under the sea.
Who on earth is the culprit...!?
And what is the trick hidden in this building!?