作为学校的传统项目，以24小时的时间走完80公里的路程，高三学生甲田贵子（多部未华子 饰）不得不和同学们完成这极具挑战性的活动。除了路程的艰辛，困扰贵子的还有一件事，那就是她的同班同学西胁融（石田卓也 饰）。贵子给自己定了一个目标，那就是在旅途结束前要和融说上话。看似简单的目标却因为胆怯、不安、疲惫等原因被搁浅，眼看天渐亮，终点即将到达，贵子能否达成她的愿望？而另一边，融也在默默关注着贵子，这段80公里的路程，既长的让人腿脚发酸，也短的不够说出一句话。承载着二人的心愿，一曲青涩又温暖的故事在这80公里的路上上演。 电影改编自日本新锐作家恩田陆的同名小说，该书获得日本第2届书店大奖。The film follows a group of high school students on a strenuous day-long hike during which they discover new sides of themselves. The story is adapted from author Onda Rika's popular same-titled novel, which earned Onda the Yoshikawa New Literary Writer's Award and the second Honya Award. Yoru no Picnic features a talented young cast including Tabe Mikako and Nishihara Aki who previously appeared in Way of Blue Sky, Ishida Takuya (Rough), Ikematsu Sosuke (Yamato), model Kato Rosa, and Kaku Tomohiro (Hana and Alice). Takako's (Tabe Mikako) high school has a unique tradition. Every year, the school's 1000 students walk 80 kilometers in 24 hours. As this is her final year of high school, Takako decides to work up the courage to talk to You (Ishida Takuya), whom she has never spoken to before. Classmates who are unaware of their relationship read something more into their awkward overtures.
