Sicily is a Hydra Sleeper agent just like Bucky Barnes, in a terrible fight against the avengers she is captured and Tony decides to lock her in the tower and see if he can help her or at least use her. Banner does a lot of testing and they find out that she is even more advanced than any super soldier they’ve come across. She’s a genius, genetically enhanced, has a couple powers, and is basically bullet proof. At only 21 she is the most dangerous threat the Avengers have come across. Add in the fact that she won’t talk to most of them while being help captive they can’t figure out how to help her. Then Peter randomly shows up and triggers a deep memory that allows her to control herself. She grows a bond with Peter and follows him around, almost like a bulletproof guard dog. She saves him from bullies at school and robbers and even a car crash. Eventually they fall in love, two superhero’s forming their own team.