When the woman that raised him is murdered a hitman turns states evidence against his employers and enters witness protection where he is sent back in time to post Civil War Texas, but it isn't long before his past and the future catches up with him.

Whilst the woman who raised him being murdered probably figures quite heavily into the way this film plays out, the real hook is the travelling back in time. So it feels like you should begin with “While in witness protection, a hitman turned states evidence is sent back in time to post Civil War Texas …”
The problem here is that the goal of your character is unclear. Is he trying to get back to his own time? Does he have to protect the town he’s arrived in from some bandits? What is the goal and what are the stakes once he’s arrived back in time?
Interesting concept for sure, great title.