In this mechanic, the consciousness of the two main protagonists—Fuyukawa Kokoro and Yukidoh Satoru—periodically swaps between their bodies.

: The transfers occur at set intervals. You must make specific choices in one location to ensure the survival of the character currently occupying the body in the other location.

The story alternates between two isolated locations during a week in January:

: A small shelter on Mount Akakura where Kokoro and other plane crash survivors are trapped in a blizzard.

: A glossary system that unlocks detailed explanations for scientific and psychological terms used in the plot, such as Dissociative Identity Disorder (DID) and quantum physics. Summary of Key Settings

One of the game's most unique and defining features is the . Feature Overview: The Personality Transfer System

: Because the player only experiences what their current character sees, you encounter information that seems to contradict what you learned in the other body. Solving the mystery requires synthesizing these two viewpoints.

: You must play through the game from both perspectives to uncover the full story. The first half is played as Kokoro, and after surviving her route, you unlock Satoru’s perspective.