Limited by his suspension and relegated to desk duty, Clark delves into Owen's cold case in which the murder investigation of a construction worker, Jozef Dworaczyk, was compromised by the events of 9/11 happening simultaneously. Andrew Lightstone, Owen's partner and mentor, was with him on the case and was called up to the North Towers leaving Owen to work the case on his own. That was the last time Owen saw Lightstone. Clark notes the lack of shell casings and no reports of shots fired to speculate that a contract hit man could have been used. He and Owen confront the drug dealer whose crack house served as the crime scene about the similar way in which his rivals were killed, and the dealer reveals the name of the hit man he suspects had targeted him but mistook Dworaczyk for him instead. When they track down the hit man, Owen coerces him to confess to fifteen murders including Dworaczyk's and is rewarded with a promotion. Clark is perturbed when he discovers that three men were wrongly imprisoned for three of those murders and Commissioner Dowdell tells him to disregard his findings. Lorraine kicks Arroyo out of the house after she discovers that he's been cheating on her. Meanwhile, Clark's father persuades Agnes to drive away with him and a volatile Deputy Mayor Holbrook confronts Clark and Margot with a gun.