Avatar: Fire and Ice - Book One: Currents

In a Water Tribe village haunted by the ghosts of its Fire Nation Colonial past, Sokka, Katara, and Kira, a girl with ghosts of her own, struggle to get by. When they find an Air Nomad named Aang, claiming to be the Avatar, the children take it upon themselves to get him to the Norther Water Tribe so he can be trained to end the Hundred Year War. But when a mysterious Fire Nation prince and his Water Tribe Slave start hunting them, Kira is forced to confront her fiery past she'd rather keep hidden. With the waterbender starting to act suspicious, Aang begins to wonder if she's plotting something.