From a young age, Taiki has been in love with Rui, the older girl next door who would play with him. He confessed this to her when he was younger, but she took it lightly. After that, time moved on and Rui graduated college along with getting married. With her older husband, Rui ended up living next door and Taiki not being able to stand seeing her happy, began to distance himself from her.
On a summer day after some time, an unexpected chance brought Taiki and Rui together to play some games. After hearing that Rui's husband is away for work, he decides to make his move. They begin a sexual relationship once Taiki forces himself on the sexually frustrated Rui. It was a relationship that was supposed to last just for the time Rui's husband was gone for work but being neighbors, they continued the relationship and couldn't go back...