一天，609号房东纨绔子弟Mum，看到一个小伙在他的床上，从他们第一次见面就上床那天后，奥秘的事情不时发作。Mum总是梦见一个奥秘的事情，半夜总会被奇异的梦突然惊醒。Mum试图经过和女人上床来遗忘和年轻女子的“情感”。但是，这甚至让他多想想他的梦中情人。然后，他把事情的点点滴滴联络起来，提出了反向平行宇宙的实际。最后，他在事实生活中遇到了Dew。虽然他们的第一次见面是Dew的最后一天，但也是他们两个相互协助改动未来的末尾！ One day, a strange man is sleeping on Mum's bed, a playboy and the owner of room 609. They both have passionate sex the first time they meet and after that, mysterious things keep happing. Mum always dreams of a mysterious event and wake up frightened in the middle of the night. Mum tries to forget the feeling with the young man by having sex with women. However, it even makes him think of the man of his dream more. Then, he connects the dots of the events and comes up with the theory of reverse parallel universe. Finally, he meets Dew in real life. Though their first meeting is Dew's last day, but also the beginning that both of them will help each other to change the future!