An MSDF submarine collides with a U.S. nuclear submarine, crushing all 76 people on board, including its CO, Shiro Kaieda. However, the crew survives. The accident is a cover story to get the MSDF submarine's crew on board the Seabat, a nuclear submarine secretly built by the Japanese and U.S. governments. However, Kaieda loads the Seabat with nuclear missiles and suddenly mutinies and flees.

In Tokyo, police officer Mari Kouda and Chinese interpreter Ryo Arikino solve cases while bonding over meals from different cultures, forming an unexpected connection through their shared experiences.

Hayami Honoka works in the sales department for a major consumer electronics company. She is excellent at her job and is respected by her colleagues. She seems like a clean freak at work and her colleagues think she is a perfect person to marry. But, in her private life, her home is a complete mess. Things there are unorganized and dirty. On the flip side, when she arrives at work, she looks perfect.

Meanwhile, Yamamoto Chihiro is Hayami Honoka's co-worker in the same department. He joined the company 3 years after Hayami Honoka. When he was a child, Yamamoto Chihiro and his two brothers did the housework at his home, while his mother was busy with her job. Because of this, Yamamoto Chihiro is excellent at doing household chores. Due to a case, he happens to learn that Hayami Honoka's home is a mess. He begins to stay with Hayami Honoka on the condition of doing the house work.

The year is 2022. It is an era of chaos, half a century after the government announced the coexistence of humans and kaijins. Aoi Izumi, a young human rights activist calling for the elimination of discrimination, meets a man named Kotaro Minami, the one called "Black Sun," who is a candidate for the next Creation King.