Reese wakes up from a coma and goes to visit his ex wife when he realizes that she's sleeping with Lucifer so he follows him to his club. Little do we know that his wife is Dr. Linda.
Lucifer talks to him about punishing the guy who is sleeping with his wife, not knowing that it's himself.
Reese is a reporter who wants to do an investigative story on Lucifer. The editor gives him the go ahead and Reese gets on it. He pitches the idea to Lucifer and he's all for it though he doesn't know the real reason for the story.
Reese talks to all the cops at the station. They all love him except for Dan. This story happened when Lucifer just arrived in town.
He joins the investigation into a serial killer to get close to Lucifer. He's following Lucifer everywhere and trying to get hold of his ex wife. He sees Lucifer make a deal when Maze comes after Reese and tells him to stay away from Lucifer.
His ex wife shows up at his office. It's Dr. Linda who wants him to sign the divorce papers, but he convinces her to hold off. Then he discovers that Lucifer is really Lucifer, but Dr. Linda already knows.
Reese learns who the serial killer is and eventually gets poisoned by the guy. Reese dies and goes to hell. He's in the same hospital where the story started. This is his hell. He never told Chloe about Lucifer. He never got the chance.