All I Want Is You <3

When Kat's brother Andrew tries to kill Blake, the person Kat loves, Kat is driven to kill him. It's part of the Agency's law, but it's part of what she needs to do to keep Blake safe. But in the process of doing that she breaks a promise to him for the first time. When she finally goes to the place he's relocated at he has a new girlfriend and he hates her. She is then enrolled in a task that has them traveling all over the world together. How will this turn out? Will he ever forgive her? Or will someone else come into the story?