A youthful taiga romance in which Ritsu Isomura, a strong-willed girl who grew up in a fishing village in Aomori, grows up despite being at the mercy of a cruel fate. Nihei is an old fisherman who continues to search for Kon, the demon king of the sea, who was the cause of the great tsunami that hit the Sanriku region in 1899, and who has been his nemesis for three generations. Then, in 1975, Nibei was informed of the appearance of a seabream by his father who was in a dream, and went to sea with his granddaughter Ritsu...!?