Doujin Fever!! Train Assault!

An ordinary office worker discovers his girlfriend's infidelity and cuts her out of his life, consumed by unresolved anger and betrayal. Taking a different train home to avoid them, he encounters Hibiki, the sister of the man involved in the affair. This chance meeting awakens dark impulses within him, and he begins pursuing a twisted path of revenge against her. The game is a trainer/management simulator where the player uses strategies, items, and skills to enact increasingly aggressive actions, with the objective of making her fall for him while keeping his activities hidden.