It was surely not love, but it was definitely love. One day, high school student Seiya Maki fell in love at first sight with a bad-looking lunch box prepared by the most beautiful girl in her class, Arisa Asahina. "I want to eat your lunch, so I want you to go out with me". Arisa feels ridiculed by his confession and angrily rejects Seiya, but she is gradually drawn to his unabashed innocence and the kindness with which he accompanies her through her troubles. However, one day Arisa discovers Seiya's secret that he can't tell anyone... Where will their relationship go, and why is Seiya attracted to Arisa's bento? Sad, bitter, loving and beautiful. A coming-of-age story.