: Ryuichi, the protagonist's only friend, who becomes a central figure in the game's darker narrative paths.

The story begins one month after a mysterious event leads humanity toward near-extinction. In the aftermath, only four survivors—two men and two women—remain on a remote island south of the capital.

: Haruto (often referred to as Kenji in some translations), a student struggling to maintain his sanity while protecting his companions.

is a post-apocalyptic adult visual novel that explores the fragility of human relationships under extreme isolation. Published in English by Kagura Games (where it is often titled Forsaken Quartet ), the game delves into themes of survival, betrayal, and the psychological impact of Netorare (NTR). Plot and Setting: Survival in Solitude

: Mayu, a childhood friend, and Airi, another survivor with a complex emotional background.

: One for each heroine. These paths focus on deep emotional connection and "loving sex" as the survivors face the apocalypse together.