The Clone Wars are over. The Purge is in place. Palpatine is Emperor. Many soldiers continue to serve whether it's with the Empire or outside of it. Crank and Bry work on the outside. They hunt their lost brothers and bring them back to the fold. Sometimes they succeed and sometimes they have to kill the lost.
Crank had just completed command training and was about to lead his first assault but Order 66 was issued. Right before firing upon his Jedi general, one of the veteran troopers shot him in the arm. He shot the trooper and 4 of his squad mates but it was too late, the Jedi escaped. After hostilities were ceased, he reported to Coruscant and served the Empire for another year. He was offered the opportunity to leave the service but only to become an independent bounty hunter. All of his contracts were to hunt wayward clone troopers...
After Order 66 was issued, Lt. Bry was on a transport and overheard a conversation between some troopers. They were criticizing Order 66 and that they shouldn't have killed a Jedi Knight. He brought them aside and shot each one. In the confusion that ensued, he explained the situation to his commander. He was sent to the brig and upon landing on Coruscant, was met at the bottom of the ramp by Palpatine himself...