Joe and Colt have a long history together.  From grade school through prison--yes prison--where they were wrongly imprisoned.  Once they served their time, they decided they were going to hunt down the man that put them there and settle the score.  Heck they could kill the man and no one could do a thing, as they already served time for the crime.  When they find him they don't expect to find a little spitfire of a woman standing up to him.