The main character is a completely normal student with nothing unusual about them. They get lost one night while returning home, left driving in a dense forest. Vision still obscured, they meet the mysterious beautiful girl Kirigiri Kyouko, and give her a ride.

However, after getting into an accident, the two of them take refuge in a nearby Western-style house. That house is in fact where Kirigiri had been headed, but with a huge tree growing inside, it’s a bizarre place.

The heroes are assaulted by a creepy Western-style suit of armor, a skull buried in the garden, and a girl who’s just like Kirigiri Kyouko…

You are the protagonist. Can you solve the mystery of the house and escape from this strange place?

[From jinjojess.tumblr.com]

The title is a parody of Otogirisou.