S1E1 · Book One: Water - Chapter One: The Boy in the Iceberg

Complete story — includes the ending

Katara and Sokka, two siblings from the Southern Water Tribe, discover a boy trapped inside an iceberg floating on the sea. They free him and he introduces himself as Aang, an airbender of the Air Nomads—a culture believed to be extinct for 100 years. Aang and his six-legged sky bison, Appa, accompany Katara and Sokka to their village. Meanwhile Prince Zuko of the Fire Nation, accompanied by his uncle Iroh, is patrolling the surrounding waters in search of the Avatar, a fabled bender who can master all four elements and restore balance to the world. Katara confides in Aang that she is a waterbender, but there are no other waterbenders in her tribe to teach her. Aang offers to take her to the Northern Water Tribe to find a teacher. An overturned fire nation warship reveals that Aang is unaware of the war that the Fire Nation has waged against the other nations of the world for 100 years, causing Katara to deduce that Aang must have been frozen for at least that long. The pair accidentally set off a signal flare on the ship alerting Zuko, who already suspects the Avatar is nearby.