Every day, a young girl wearing a mask stands by the beach and sings a nostalgic melody. After experiencing two sudden heart-wrenching partings when she was only a child, Nino Arisugawa has been singing her songs to the ocean, bound by a promise made with her two childhood friends—her first love, Momo Sakaki, and a boy who composed music, Kanade "Yuzu" Yuzuriha. Having never met each other, the boys both individually promised that if Nino was ever separated from them, her voice would be the beacon to reunite them once again.
中条あやみ
as Nino Arisugawa
志尊淳
as Kanade Yuzuriha
小関裕太
as Momo Sakaki
真野恵里菜
as Mio Suguri
磯村勇斗
as Ayumi Kurose
杉野遥亮
as Yoshito Haruno
