Kuroneko to Waltz

Hirose is upset after discovering that Matsui, his boyfriend, has cheated, giving the excuse that he sometimes prefers seeing a girl's body over a man's. At a shrine, Hirose expresses his anger and cries, vowing to curse Matsui. The following day, he encounters a black cat outside Matsui's apartment, bearing a scar identical to Matsui's. Meanwhile, Matsui appears to have vanished without a trace.