A cure for a certain disease. The side effect was to "forget" a certain person. Seto Yukiya is a man who has "forgotten" his ex-girlfriend. Mikoto Hayashi, a woman who has had a crush on Yukiya for many years, lies to him that she was his lover. Chisa Nagato, a wife who has "forgotten" the loss of her beloved child. Her husband, Kojiro Nagato, tries to pretend that they never had a child. This is a story of two couples, a man and a woman, and the people who stand by them...