Some Where We Belong (Captain America Love Story)

Two Siblings, Nellieton and Lucas Granite are sent on a mission to track down a dangerous weapon. They are almost caught by the Avengers but manage to get away, however they don't have the weapon. They get tortured and are given a new mission to kill Captain America. They track him down and have him right where they want him. Nellieton is about to kill him but she looks at the pain in his eyes and can't kill him. She decides that her and her brother should seek refugee with the Avengers. Captain takes them to the head quarters and they meet the rest of the Avengers.
What Do The Avengers Think Of The Siblings?
Do They Accept Them?
Do They Want To Destroy Them?
What Happens When Lust And Love Are Involved?

{P.S: I'm sorry if parts aren't up quick, but I'll try get a part out everyday}