Set on a remote island in Ishinomaki, Miyagi Prefecture, this human drama depicts the strange shared life and family rebirth of two fisherman brothers and a manga artist from Tokyo.

A 100-year-old resident of a Lake Biwa nursing home dies mysteriously. Did a respirator keeping him alive suddenly malfunction, or was he murdered? A young detective on the case meets a female caregiver. The investigation runs into a dead end, but the two fall into a passionate but forbidden relationship. Terrifying memories emerge from the vast, deep lake to ensnare the detectives on the case, the caregivers, and a reporter trying to uncover a hidden past.

Makoto Takashima is a young security guard who's inherited a huge debt from his father. Desperate to pay back his debts – and to buy a proposal ring for his girlfriend Kiyomi – he agrees to do a lucrative job to a yakuza named Masui: stealing a stock prediction AI program from his company. When Makoto tries to extort more money from Masui, Masui kidnaps his little sister Yui. However, nothing is as it initially seems: the AI program is also targeted by a group of professional swindlers, a legendary killer-for-hire, and a young female assassin.

When Mikio Natsuno obtains a residency certificate, he is stunned to find the name of a woman he has never met listed as his wife. Apparently, he has been "married" for six months without knowing it. Who on earth is the stranger who decided to become his wife? After a frantic search, Mikio finally discovers her—an eccentric young woman with a striking personality who simply says, "I thought I could keep myself together if I were at least married," offering no further explanation. And so, their uneven, unpredictable relationship slowly begins to take shape.