Mac meets with Lieutenant Sythe and asks him if Flack is reported AWOL. He says Flack is taking a day off. Sythe says he can get in trouble for covering for him.

Sid tells Stella that Richard broke most of the bones in his body. Sid says the jumper was shot in his chest. Stella figures the shot was fired from at least three feet away. Sid figures the suicide was staged and wonder if the Compass killer is responsible. He says he found some fibers. Stella figures the killer dumped the gun in the water.

In the water, Mac instructs Sheldon who is diving to be careful. Mac gets a call from Danny who tells him Flack is not in his apartment. He says it looks like Flack has been drinking. Danny searches the closet where he finds Flack's gun. Mac asks him to check the local bars.

Underwater, Sheldon says there is a lot of trash there. After Sheldon uncovers a compass, Mac figures the Compass Killer is back. Mac suspects the compass dropped with the victim. The see the needle was glued to point east. Stella notices there is someone watching them from above. Mac calls for a search team. Later, Mac realizes they lost their suspect. He sees a note on the railing that says, 'I should have stayed awake, I'm sorry.'