Avatar: The Legend So Far

Synopsis
The Legend So Far is a recap episode of Avatar: The Last Airbender narrated by James Garrett, the voice of Avatar Roku. In this recap, Roku retells some of the events that have occurred in Aang's journey before episode eighteen, "The Waterbending Master", and provides a sneak peek of the episodes still to come. It served as an introduction to the three-part Book One finale, which began with the episode "The Waterbending Master".

(Source: Avatar Wiki)