On July 27th, university student Aoi Hinata (Miwa) has an accident. When she wakes up, Aoi Hinata finds herself in a classroom from one week before the accident. At that time, her childhood friend Riku Hasegawa (Kentaro Sakaguchi) tells her "I will tell you a secret. I can turn back time." Aoi Hinata and Riku Hasegawa like each other, but never expressed their feelings. They share their feelings for each other and go back to one year earlier. They spend their time happily as girlfriend and boyfriend, but there is a big secret behind the time slip. In addition, July 27 is approaching.

Three murder cases take place in Tokyo. Numbers are left at the murder scenes, possibly hinting at where the next murder will take place. An investigation begins of the serial killer and Detective Kosuke Nitta (Takuya Kimura) works on the case. He believes the next murder will take place at Hotel Koruteshia Tokyo. To catch the killer, Kosuke Nitta goes undercover and begins working at the front desk of the hotel. Naomi Yamagishi (Masami Nagasawa) works at the front desk of Hotel Koruteshia Tokyo. She is selected to train Kosuke Nitta for his front desk job, but they can't get along. Kosuke Nitta is focused on catching the killer, but Naomi Yamagishi prioritizes the safety of the guests. As they begin to understand each others differences, they also begin to build a trust between each other. Who is the murderer? --asianwiki

A world wide electrical outage occurs. Everything that requires electricity comes to a stop. Tokyo is nearly ruined. Yoshiyuki Suzuki (Fumiyo Kohinata) decides to escape from Tokyo with his family.