This episode is part of the Avatar Book Two - Earth
Avatar The Last Airbender Episode Guide ~ via Wiki
While on the way to Omashu, Aang and the crew meet a group of traveling bards, who take them through a vast tunnel known as “The Cave of Two Lovers”. In the cave, Aang, Katara, and Appa become separated from Sokka and the bards. Elsewhere, Zuko and Iroh are sheltered by kind people after Iroh “accidentally” drinks the tea from a poisonous plant. Song, a young and compassionate healer, shows Zuko the effects of war from a normal citizen’s perspective.