一天，609號房東花花公子Mum，看到一個(gè)小伙在他的床上，從他們第一次見(jiàn)面就上床那天后，神秘的事情不斷發(fā)生。Mum總是夢(mèng)見(jiàn)一個(gè)神秘的事件，半夜總會(huì )被奇怪的夢(mèng)突然驚醒。Mum試圖通過(guò)和女人上床來(lái)忘記和年輕男子的“情感”。然而，這甚至讓他多想想他的夢(mèng)中情人。然后，他把事件的點(diǎn)點(diǎn)滴滴聯(lián)系起來(lái)，提出了反向平行宇宙的理論。最后，他在現實(shí)生活中遇到了Dew。雖然他們的第一次見(jiàn)面是Dew的最后一天，但也是他們兩個(gè)互相幫助改變未來(lái)的開(kāi)始！ 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!