Kurata Izumi's memories of Takatsudo Shin end at middle school graduation when Shin told Izumi he never wants to see him again. Now Izumi is a single father whose son is in love with Shin's nephew. They're forced to interact, but Shin doesn't seem to remember what he said to Izumi. Add Izumi's yakuza brother-in-law Sawaragi into the mix... Sequel (actually spin-off): Aiso Tsukashi.