Love Is Indivisible by Twins
恋は双子で割り切れない, Futakire, Koi wa Futago de Warikirenai
Jun Shirasaki and the Jinguuji sisters are childhood friends and neighbors. When Jun's first girlfriend, the older sister Ryuumi, breaks up with him, she says something that complicates the three people's relationship, their first loves, and their romance—?