Where earlier shows might have hinted at such an atrocity for adult viewers’ benefit, “Avatar” is overt, taking seriously its young audience’s capacity to confront the consequences of endless war. He is, he discovers, both the Avatar and the last of the Air Nomads. In the third, Aang returns to the temple where he was born to find the aftermath of a genocide. The first two episodes are largely what you’d expect: world-building punctuated by moments of whimsy. The series begins a century later, when a twelve-year-old boy named Aang is discovered and revived by a pair of Water Tribe teen-agers-and the Fire Nation is well on its way to global conquest. Just as the Fire Nation launches an attack, he vanishes. In a world where nations are defined by their connection to one of the four elements-water, earth, fire, and air-maintaining the peace falls to the Avatar, the only person who can achieve mastery of them all. Like all such stories, “Avatar” (created by Bryan Konietzko and Michael Dante DiMartino, and no relation to the James Cameron blockbuster) demands some exposition. Photograph from Nickelodeon Network / Everett The Nickelodeon cartoon “Avatar: The Last Airbender”-now on Netflix, and more popular than ever-functions as both a comfort watch and a means of catharsis.
