Nagasaki in 1986. Hisada, who lives with her affectionate parents and her younger brother, although there are many quarrels between couples, is a fifth grader who loves Yuki Saito and Exogini. Hisada decides to go to Boomerang Island to "see the dolphins" with Takemoto, whose house is poor and avoided by his classmates. Drowning in the sea, getting entangled in the Yankees, and having a lot of trouble, but as the friendship between the two deepens as a result of this adventure, a sad incident that presages farewell occurs.
Banke Ichiro
as Takaaki Hisada (young)
Konosuke Harada
as Kenji Takemoto (young)
尾野真千子
as Ryoko Hisada
草彅剛
as Takaaki Hisada
竹原ピストル
as Hiroshige Hisada
貫地谷しほり
as Masayo Takemoto
岩松了
as Uchida
村川絵梨
as Yayoi
福地桃子
as Ako
Goriken
as Takeo Ouchida
Rintaro Hachimura
as Kanayama
茅島みずき
as Yuka
