The Mystery of the New Moon and the Black-haired Inuyasha Inuyasha : Season 1 Episode 13

Half demon Inuyasha's secret is that he becomes human once a month. That day, Inuyasha and the gang meet Nazuna and stay at a mountain temple. They fall into Kumogashira's trap and the sacred jewel shards are taken away from them. Inuyasha is injected with poison!