Thanks to the first part of the WSJ interview with Mike and Bryan we know now when Book 3 will take place in-universe. [caption id="attachment_8330" align="aligncenter" width="600"]K214 Korra announced the change to the world, how will the world react.[/caption]
Will it be set in a future time period right after the events in “Spirits”? DiMartino: It comes pretty close in the time period, a few weeks after Book 2 ends.
Makes sense in that the Book is called Change, that change would be felt the most soon after Book 2. It would be very fun to see Spirits randomly roaming around republic city, watching Pro Bending matches. Carrot Guy strolling around the Dragon Flats District. There are other things mentioned in the interview, but nothing really news worthy. There is a second part of the interview coming at some stage.