Jaime Lannister is a megalomaniac, he's power hungry. Since his release from captivity and the Lannisters winning the Battle of Blackwater – he's been unstoppable. He's decided that instead of keeping his alliances, he's going to start taking what he wants. The list of things he wants apparently includes your home.

In the process of taking over your home, forcing your father into submission along with all of his soldiers; Jaime found you. You had tried to hide, you had tried to run, you had tried to defend yourself, but it was no use. Jaime took you back to King's Landing with him.