In the original timeline, Amy Preston was born in 1990. She had a degree in sociology and a black belt in karate. She often tried to get her half-sister, Lucy Preston, to leave their mother's place of work in search of better opportunities, but Lucy is reluctant to do so.
In the altered timeline, Carolyn and Wallace never meet, causing Amy Preston never to be born. Since her disappearance, Lucy has continued to complete missions to stop Garcia Flynn. Lucy uses the hope that some day she'll be able to go on a mission to save Amy as motivation to continue. (“Pilot”)