Former college buddies Horaguchi and Okawa suddenly reunite on a whim after 15 years apart and try to resume their friendship by planning a trip together. Meanwhile, Okawa’s live-in girlfriend Kaede and the pair’s old friend Kyoko get roped into joining them. Soon, the four head off on a trip together with the goal of sharing sukiyaki by the sea.

Kako (Fumi Nikaido) is a female high school student. She lives at a restaurant run by her family in Kitashinagawa, Tokyo. Unexpectedly, Kako’s aunt, Mikiko (Kyoko Koizumi), suddenly appears. Kako thought her aunt died 18 years ago. Her whole family is embarrassed by Mikiko’s appearance due to a past incident caused by Mikiko. Kako is also irritated when Mikiko lives in her room. They spend the summer together.