Kazuya's dream of living together with Mizuhara, the perfect girlfriend, has finally come true-and it's her birthday! She made it clear she doesn't want a gift or a celebration of any kind, but will Kazuya really take no for an answer after she so graciously allowed him to stay with her? As he struggles to figure out a solution to his birthday dilemma, who should pop back into his life but Sumi-chan! Will her surprise appearance lead to a development in Mizunomiya's investigation?!