Yu Yu Hakusho 1x8

With two artifacts under his belt, Yusuke heads for his most dangerous challenge yet – the ruthless demon Hiei. But unbeknownst to Yusuke, Hiei is chasing him, and kidnaps his girlfriend Kayko! Unless Yusuke can retrieve the antidote inside Hiei's Shadow Sword, Keiko will become a brainless, monster slave! Can Yusuke close the case?