‘Avatar: The Last Airbender's Most Intense Episode Is Still Its Most Devastating 25 Minutes

For a series remembered for its exhilarating bending battles and sharp sense of humor, Avatar: The Last Airbender has never shied away from heartbreak. “The Tales of Ba Sing Se” leaves audiences in tears, “Zuko Alone” strips away the Fire Nation prince’s defenses, “The Southern Raiders” forces Katara (Mae Whitman) to confront the man who murdered her mother, yet none of those episodes is quite as quietly devastating as “Appa’s Lost Days.”