It is set 3 years after Aang defeated Ozai. NOT MY ART credits to @aimaduragon on Instagram Suki went to the fire nation to be Zuko's guards as people were becoming a threat to his throne, because of this Suki and Sokka thought it would be wise to not continue their relationship long distance as Sokka was helping Aang with a new city concept and was training new souther water tribe warriors. Now Zuko has come to visit Air temple Island so Aang can help him with some ideas for the firenation. Somewhat canon.