When Mio was young, she lost her parents in a great flood and also became separated from her best friend Noe. Afterwards, Mio found her talent in cooking and eventually became a cook. Meanwhile, Noe has become an oiran (high-ranking courtesan).

在2月29日诞生的中学生西野敦史（沟端淳平 饰）和竹宫芽衣（南泽奈央 饰）因为这份特殊的缘分而结识，而他们其实早已在数年前就已相遇。特殊的四年一次的生日，和这份命定的缘分，让敦史和芽衣不由自主的靠近彼此。可这份纯真的感情却因外外界的种种事情而被阻止和中断。敦史谜样的家庭和过去，芽衣妈妈对这份感情的阻止，周围同学发生的各种事件让这对年纪轻轻的中学生经历了太多伤痛。发生了各种事情之后，敦史决定默默离开芽衣。二人在不同的地方各自成长着，时间在流逝，伤口在愈合。连在二人指尖的看不见的红线冥冥之中牵引着二人再度重聚…… 本片改编自大人气的手机连载小说。

After a series of chance meetings a shiftless motorbike enthusiast Ko begins a romance with a carefree girl Miyo, after teaching her to ride. When Miyo proves herself a biker prodigy Ko begins to fear that she is destined to crash. Shéa Le Poidevin and Rafi James star in Obayashi's magnum opus.