きみの最後の一カ月、恋はオパール色になって•

Kimi no Saigo no Ikkagetsu, Koi wa Opal-iro ni natte

In the summer of their second year of high school, Tomoya and his childhood friend Ayano set out on a journey without a set destination, sharing their painful secrets as they search for "true happiness."<br><br> As the "black lump disease," in which people die and turn into black lumps, spreads on the internet, Tomoya Sakuma, a second-year high school student, begins to connect with his childhood friend Ayano Haruhara after his mother's suicide. Though it takes him a long time to confess his feelings, Ayano becomes his beloved girlfriend. However, their time together is short. When summer break arrives, they decide to embark on a slow train journey with no set destination, filling it with things Ayano wants to do. But Tomoya doesn't yet know the truth that awaits him ahead..."<br><br> (Source: Futami Sara Bunko, translated)