You can draw and fire a pistol with lightning speed, attacking before the Combat Initiative sequence begins. If you are not Engaged, you may make a single attack with a loaded weapon with the Pistol Trait before the first turn of the Round. This attack uses your Action for the Round. If multiple Characters use Fast Shot, resolve their attacks in Combat Initiative order.
When your turn arrives, you act as normal, but cannot make another attack.

Core Book, Page 119