Sayaka Minami is a 30 years old Japanese woman, very capable in her job and not at all experienced in love. In fact, she never had a boyfriend in her life because she has always been in one way love with her childhood friend Ryosuke Sagisawa for 15 years! Lack of having real satisfaction of work and love in her life made Sayaka afraid of taking actions. But one day morning, Sayaka woke up, shockingly found a stranger just in front of her!! “What is this? Who is that guy? And what’s going on??”Despite her shock, the stranger introduced himself as Machida and tells that Sayaka and he has been dating. More surprisingly, they are living together. Somehow Sayaka has lost her memory for the last 3 months and she made the very first boyfriend! The worst part is that in that last 3 months, Sayaka has lost her virginity!!! She decides to bring her lost memories back and find out what has happened with the sadistic stranger Shohei Machida. Can Sayaka retrieve her lost memory? And where will Sayaka’s love head to? As Sayaka’s the bizarre cohabit with Machida starts, their relationship starts changing…