1x11 - Ghost Hunt

Masako requests Naru investigate a park where over six months, couples have had water dumped over them from thin air. The team, excluding Lin, split up at Masako's suggestion into pairs and they soon attract the spirit of a woman. Taking possession of Masako's body, the woman explains she died soon after being cheated on by her boyfriend. Mai convinces her to let go and move on to heaven, but not until they have forced the cheating partner to acknowledge the hurt he caused.