At the station, Stahl reveals that Glenn had a degenerative disease and was trying to use the robotic parts to prolong his life. His victims were test subjects for his cybernetic parts. The parts worked for a while, but when they started breaking down after 10 years, he began killing again. Kennex thinks that his dad found out about the missing parts from evidence and was killed for it. Maldonado says Officer Grant could've been framing Kennex's dad for stealing the evidence before Glenn killed them both. Costa gets released and the charges are dropped. Maldonado congratulates Kennex for finishing his dad's work and clearing his name.
Dorian receives glowing reviews from the squad, particularly from Kennex, who claims that Dorian is the reason he's staying on the force. In the end, Dorian's assignment is renewed. (So meta!) The season ends with Dorian finding Kennex at a ramen bar just like in episode one. He gives Kennex a gift as a thank you for the glowing review -- a new, souped up robot leg. Dorian is so touched by what Kennex said in his review that he starts to tear up. But before things can get too touchy feely, our favorite human/robot buddy cop duo are called into duty.
So we end the season (and potentially the series) with a solid episode that highlights the strengths of the Kennex/Dorian relationship at the show's core. Sure, I would've preferred to learn more about John Larroquette's Doctor Vaughn and the potential robot army he's building beyond the wall. But at least the writers wrapped up one dangling mystery and gave us some quality Kennex/Dorian bonding time. Hopefully we haven't seen the last of TV's best (ro)bromance.
Oh, and apparently this whole time we've been in the city of New Pittsburgh. Huh. Didn't see that coming. I guess in the future, Pittsburgh is going to look a lot like San Francisco crossed with Vancouver.