Our CSI’s all receive anonymous envelopes of pieces of cut plastic which turn out to be a puzzle directing them to an address. They show up moments too late as they arrive to find Janice Potter shot dead by a single bullet to the head. We discover the weapon was set up in the bushes and triggered remotely.
Janice’s husband comes in with yet another anonymous clue left in his mailbox leading the CSI’s to the next location. They arrive at the Dade University swimming pool where we find Professor of Psychology Neal Brusatti dead in the water. As they canvas the area they discover their next clue on the pool cover, a painted image of a fleur-de-lis on fire.
We also discover that Janice Potter was secretly participating in a psych research study where she was to shock the subject with electricity based on their answer to certain questions. However, Janice realized that Melissa Walls, the student conducting the study for her thesis, was manipulating the data to fit with her theories. Walls, who was recently fired, would be our likely doer but further evidence exonerates her. Our killer seems to be targeting anyone connected with the psych department and our team provides protection for the professors.
We discover that our murderer is actually one of the professors we were assigned to protect. Professor Bob Starling was upset because he wasn’t given tenure and was out to seek revenge. While handcuffing Starling, a card drops from his pocket addressed to Horatio where when opened the “ring around the rosy” nursery rhyme plays. We cut to CSI where we begin to see Ryan, Walter and the other CSI’s drop to the floor unconscious. Delko get’s reinstated as a CSI in this episode.