From the pinnacle of happiness to the abyss... Life, one step ahead is darkness! One day, Kouji had an epiphany and confessed his feelings to Chiharu, his neighbor. Although she seemed taken aback, she accepted his confession and they began dating. His sincere approach seemed to work well, as Chiharu quickly warmed up to him and soon enough, they were sharing a bed together. For Kouji, this was the ultimate bliss. However, just when he thought they would reach their goal, the dark shadow of Chiharu's past emerged, casting a sinister light upon their relationship...

幸せの絶頂から奈落へと…。人生、一寸先は闇！ コウジはある日一念発起。隣に住むチハルに好意の告白をした。面食らった様子の彼女だったが、その告白を受け入れ、二人は付き合うこととなった。初々しいコウジの接し方が良かったのか、チハルもすぐに打ち解け、二人は床を共にするようにまでなった。コウジにとってそれは幸福の絶頂。このままゴールインかと思われた矢先、チハルの過去が暗い影と共に現れたのだった…。