It was five years ago that I started a sex friend relationship with my son's friend, Kitayama-kun. When her husband's affair was discovered and she was heartbroken over the cracked marital relationship, her son brought her in, Kitayama-kun. Kitayama-kun took advantage of the opportunity and stole my lips. While I was upset, Kitayama-kun told me that he fell in love at first sight and expressed his passionate feelings for me. I was so excited that it didn't take long for Kitayama-kun and I to become friends. And before they know it, five years have passed in a relationship that was supposed to end as a temporary mistake...