As the second eldest son in a big, poverty-stricken family, Kouno Kazuomi has to look after his younger siblings. At school, he's the low-energy-consuming cool boy. He was only devoted to his family before, but his senior of 2 years, Makise Koutarou, invites him and now he's part of the Gardening Association. Despite being bewildered by Koutarou's excessive physical contact and friendliness, Kazuomi slowly opens up to him: the first senior he got along with. However, he witnesses Koutarou, number one popular guy in school, in a scene showing his free-spirited nature regarding relationships, and Kazuomi's heart trembles in pain. A riajuu senpai that can't stay long in a relationship and an innocent kouhai who doesn't know love – their sweet, melting youth begins.