S4, E7: It’s Friday the 13th and everyone at 15 Division is prepared for a night of pranks and superstition - but it’s no joke when Marlo and Gail get called to a downtown ravine and discover human bones. As the sun goes down and the bones are identified, Swarek realizes it’s a 15-year-old missing persons case he worked on with his old Training Officer, Charlie Fitzgerald. Swarek reunites with his old T.O. to investigate previous suspects and in the process gets a closer look at his mentor. Meanwhile, the weirdness of the night finds its way into the station as Chloe and Dov can’t agree on how to deal with a witch and her disgruntled client. In the end, Swarek must decide whether he wants to continue on his mentor’s path or change how he relates to the people closest to him.