供职于某广告代理公司的青年奥田浩介(松本润 饰)跟随前辈拜访客户,谁知竟在对方的公司重逢了青春时代的初恋女友渡来真绪(上野树里 饰)。当年浩介(北村匠海 饰)在江之岛念书,班里突然转来一个长相可爱但是头脑和运动神经都不太灵光的女孩真绪(葵若菜 饰)。在真绪受欺负的时候,浩介果断出手相助,此后他们俩在一起学习、聊天、接吻,青涩的恋情在阳光下悄然绽放,直到浩介突然搬家离开。十年的时间并未隔断浩介和真绪的牵念,他们的爱情重新注满热情与温度。两人相恋相爱,结为夫妇。当一切看似驶向幸福的彼岸之际,真绪的身体却突然迅速衰弱。浩介还不知道,他将发现一个令他无法释怀的感伤秘密…… 本片根据越谷治的同名原作改编。A salesman named Kosuke Okuda happens to meet Mao Watarai,a friend from his middle school days. Back then, Mao was bullied, but now she is an attractive woman. Kosuke and Mao fall in love and decide to marry, but Mao has a secret.