Ruby Stark is the daughter of the arrogant Tony Stark- she has existed for 16 years unbeknownst to him. She hasn't lived the same easy and extravagant life as her father, she went to bed hungry more nights then not. Her mother brought her to America in hopes to rekindle her love with Tony, but succumbed to a disease shortly after crossing the border, leaving Ruby all alone.

Set after Korra has died, and the new Avatar, Avatar Saishū, has been born. The only problem is she has no idea what an Avatar is until Aang appears and tells her she is one when she is 16. She has been living in an abandoned Air Temple with her mother and four siblings and has no real idea of what life down below is like, or how the non-benders have been treating benders.