2024年夏。墨田区桜丘総合病院に勤務する中堅看護師、高橋沙穂。仕事はデキるが、やる気がなく、まるで青春を失ったかのように憂鬱な日々を送っていた。沙穂は、かつて名誉婦長を務めていた、寝たきりの入院患者・雪野沙衣に、無力感や報われない状況など、自身の悩みを密かに打ち明けていた。しかし次の瞬間、突然大きな地震が発生。落下物から沙衣を庇った沙穂は意識を失ってしまう。
沙穂が目を覚ますと、そこは病室ではなく、ジャングルだった。なぜか、軍服姿の女性たちから「沙衣」と呼ばれていた。彼らは、自分たちがフィリピンにいることを告げる…。やがて沙保は、彼女を助けてくれた藤原ミツ、菅野蕗子、佐治誠が、負傷した沙保が運ばれた野戦病院で働く看護師と軍医であること、そして戦時中の1945年（昭和20年）にタイムスリップしてきたことに気づく。不思議なことに、彼らは幼い沙保の姿をしている…。
Summer of 2024. Takahashi Saho is a mid-career nurse working at Sakuragaoka General Hospital in Sumida Ward. She is good at her job but has no spirit and is low-spirited as if she has lost her youth. Saho has been secretly confiding her worries, such as a sense of helplessness and an unrewarding situation, to Yukino Sae, a bedridden inpatient who was once the honorary head nurse at the hospital. But the next moment, a huge earthquake suddenly occurs. Saho loses consciousness when she shields Sae from something falling on her.
When Saho wakes up, she is not in a hospital room but in a jungle. For some reason, the women in military uniforms call her "Sae". They also tell her that they are in the Philippines... Soon, Saho realizes that her helpers, Fujiwara Mitsu, Kanno Fukiko, and Saji Makoto, are nurses and military doctors working at the field hospital where the injured Saho was taken and that she has traveled back in time to wartime 1945 (Showa 20). Strangely, they are in the form of a young Sae...
