The Release (S01E18)

The Animorphs make a grim discovery: Yeerks inside their human hosts are mysteriously dying. As Controllers suddenly drop unconscious or collapse in pain, the team realizes the Yeerks are perishing while still attached. With no time to waste, they race to separate the dying parasites from their victims before the hosts die too. In a desperate battle against the clock, the Animorphs struggle to save the freed Controllers, knowing each rescue is a race between life and death.