Bucky is an Avenger, Steve saved Bucky from hydra. Bucky and Steve are from the 40's and even went to war together, but got frozen and are now Avengers. But Steve went back into time, not seen again.

Bucky has been with Sam, helping him. When suddenly there is a new Avenger that remind everyone of Steve, her name? Jax Rogers, the daughter of Steve Rogers and Peggy Carter. Even uses Steve's old shield.

Bucky sees her and falls in love, but is also confused as hell when he sees her.