Ava was mentioned by Theodore Fallon during Martin Rank's visit in Fragment Fifteen. When Nate was young, he ha little understanding of how his powers as an adept function, causing him to "unhook" people and objects from one time and displace them in another time without realizing that he needed to exchange them for something else. This caused various objects around the Fallon household to go missing. When Ava's engagement ring was found in an untouched memento box in the roof of the Fallon house, Teddy realized it was serious, that his son was an adept.
When Nate was nine years old, he learned that his parents were passionate about tracking down Savarina's canon. In order to impress his father, Nate displaced Ava in exchange for the lost sixth book. She had been transported to the 16th century where she died, alone. It was weeks before her body was returned to the present, plucked from a potter's field.