Namikawa Kenta (Ino Kei), who works at a commercial production company, and Natsume (Ihara Rikka) are a happy couple that everyone envies. However, Natsume is dissatisfied with Kenta's excessive doting. Kenta, who has no way of knowing what is going on in his wife's mind, one day sees a message from a person named "Yamacchi" that arrived on Natsume's smartphone. It says that the two of them have made a promise to meet at a hotel, and Kenta is shocked that Natsume may be having an affair.The next day, Kenta decides to find out the truth from Natsume, but just as he is about to do so, Natsume is killed in a traffic accident as she leaves the house. That night, Kenta is left alone and stunned by the sudden turn of events. He sheds tears in his room, but the moment the clock strikes 11:22, Natsume, who was supposed to be dead, appears before him. Moreover, Natsume says that it was Kenta who died in the accident...

At the same time every day, Kanta (Ino Kei) is able to mix with Natsume's (Ihara Rikka) world and spend a few minutes with her. He calls this phenomenon "mixing". Meanwhile, there are only three days until Natsume meets Yamatchi at a hotel. Who will it be? Meanwhile, Natsume, who lives in a world without Kanta, behaves bravely, as if she doesn't need the concern of those around her. However, when she is cleaning up Kanta's desk, she finds a bunch of notes addressed to Kanta from Natsume... Unable to contain her memories, Natsume stops by a game bar on her way home from work and gets drunk. That night, Kanta, who has mixed with Natsume's world, is surprised to see Natsume sleeping drunk in a messy room. Moreover, he finds men's underwear and a note saying, "I'll put the key in the mailbox" in the laundry..

On Saturday night, Natsume (Ihara Rikka) made an appointment to meet Yamatchi at a hotel, but when she didn't come home by the time of the mixer, Kanta (Ino Kei) grew impatient. Meanwhile, while enjoying her mother Kaede's (Minamino Yoko) home cooking at her parents' house, Natsume realized that she had been ignoring the discomfort she felt towards Kanta in her married life, and she began to worry about the future of their marriage. Then, Maruyama (Nomura Kota), worried about Natsume, could no longer suppress his feelings of love and went out of control. Meanwhile, Kanta was about to question Maruyama about his relationship with Natsume. Then, Riko (Saito Nagisa) came over and Kanta was caught up in something Maruyama said, and he asked how long they had known each other... Meanwhile, Natsume's uncle and detective Minoru (Nozoe Yoshihiro), who was investigating Kanta's accidental death, found something that brought him closer to the truth of the death..

When Natsume hears from her uncle Minoru that Kanta's hit-and-run may have been murder, she realizes that Kanta, who lives in another world with her, is in danger. However, she thinks that if she tells Kanta about it, he might go out of control.

Although she once chose to break up with Mikita, when she found out that someone was trying to kill them both, she decided to team up with Mikita to save them both. In fact, it is said that the culprit may have known about their schedules.

Kanta begs Minoru to get security camera footage from the apartment building. The people from the advertising company join the investigation and review the footage, successfully identifying the culprit. The culprit, who was arrested in Kanta's world, begins to reveal an unexpected motive during Minoru's interrogation.

One day, Hanako Mizusawa, a friend of Kanta's from his school days who is currently working as a dancer overseas, comes to visit Natsume. She overwhelms Natsume with her dazzling beauty and dignified presence, and tells her about her romantic drama-like encounter with Kanta.

As strange events occur that seem to foreshadow the end of Mix, and Kanta and Natsume become anxious, Natsume's father Goro comes to visit Kanta. Goro, who left his family behind when Natsume was a child, says he regrets learning of his daughter's death.

Natsume finds out she is pregnant. She is surprised and happy, but thinking about the end of the mix, she wonders if it would be better not to tell him about it. Meanwhile, Kanta notices that the mix time is getting shorter..

The day after Natsume reveals her pregnancy and the couple shares their joy, Mix suddenly doesn't wake up. Mikita can't sleep a wink, fearing he'll never see Natsume again, and Natsume spends the night feeling the same way Mikita does.

Natsume, who reunites with Tamura and Riko from Kanta's world, is touched by the warmth of her friends and thinks about the future of raising a child with Kanta. Meanwhile, Tamura suggests bringing Natsume to this world, and Kanta also holds a glimmer of hope.