Bucky has been an Avenger for a few years, since being saved from Hydra. He has a metal arm and is 106, but looks 23. Tony and Bucky don't get along, at all and always fight

Tonys older sister is in Tonys lab while Tony is on a mission, no one knows about her yet. She's different, she looks younger then Tony because she was frozen at hydra and she has powers

Bucky walks walking into the training room, but hears music coming from the lab and decides to check it out