洸と同じ悲しみを知る、女の子―。
吉岡双葉（出口夏希）と馬渕洸（櫻井海音）は次第に想いをたぐり寄せ、文化祭の日に急接近する。洸の本当の気持ちを知りたい双葉は洸に想いを伝えようと決意。そんな2人の前に、洸が中学時代に転校した長崎で出会った同級生・成海唯（藤吉夏鈴）が現われる。洸は同じ悲しみを知る唯を放っておけず、双葉と菊池冬馬（曽田陵介）の目の前で唯を抱き寄せる。あと1ミリの青春が近くて、遠い―
Futaba Yoshioka and Kou Mabuchi gradually develop feelings for each other, and on the day of the school festival, they suddenly grow closer. Wanting to know Kou’s true feelings, Futaba decides to tell Kou how she feels. Then, a classmate, Yui Narumi, whom Kou met in Nagasaki when he was a transfer student during his junior high school days, appears in front of the two. Kou cannot leave Yui, who knows the same sadness, alone and embraces her in front of Futaba and Toma Kikuchi.
