CBS

A sailboat race to Staten Island takes an unexpected tack when one of the boats nearly collides with a dead scuba diving instructor. Autopsy reveals this was no accident and trace evidence leads the CSIs underwater to an artificial reef made of discarded subway cars stacked up at the bottom of the Hudson where they find the dead diving partner of the first victim. Tissue analysis reveals both were killed near a shipwreck from the 1700s. Danny and Hawkes explore the sunken vessel and find evidence leading them to two young students who tricked the scuba diving instructors into helping them navigate the waters under the guise they were looking for a sunken treasure. When Mac and Stella go to question these students, they stumble onto something much larger; a plot to blowup a helipad along the East River where a controversial foreign official will be landing before heading to speak at the United Nations.