Mac and the team are called to Ellis Island when a working class janitor is found hung to death. On the victim's body was a cryptic suicide note but the suicide theory is quickly discarded when the victim's cell phone reveals a call from his wife was answered several hours after his death; the murderer being the sobbing voice on the other end. Mac sees a message in the evidence as the killer leaves an antique compass pointing south and all the items used in the murder reference the 1960's. We are soon introduced to the killer and get a glimpse into his life as our team of CSIs search for him. When the killer mails Mac a second antique compass pointing north, he knows there is a small window to find the killer's next victim before he strikes. Pollen residue inside the second compass leads them to a garden conservatory where they discover a second female victim, also with a cryptic suicide note attached to her body and hung in the same manner as the first. Mac hears a message Sid left for him mentioning that the female victim's husband is coming to view the body. Mac, fearing for Sid's safety, frantically runs to his office knowing that the victim is a widow and the killer is impersonating her husband. Mac finds Sid alive but also finds a third compass where the killer stood; this one is spinning out of control. The investigation into the Compass Killer will continue in future episodes.