Flint has to change or die. He's a police officer on the beat for the last seventy years, still physically young due to advances in medical science, it's all he's ever known. 
Around him, all the new recruits have robotic partners who do their paperwork and chase down the more agile criminals for them. 
After he loses his partner, he's got to choose. To continue on the force, he'll have to take on one of these new androids, but he doesn't it's forced retirement.
To avenge his partner, or leave the force? There's at least one more job to do. The robot's got that long. It better be good.