While riding the subway home, Danny sees a dead man on the tracks and stops the train before impact. Although the initial thought is that the 19-year-old college student died after subway surfing, Mac, Lindsay and Danny deduce foul play when they learn that he and a friend had been partying all over town leaving angry suspects behind. A shark's tooth is found embedded into his hand and four tropical fish are discovered in his stomach. Meanwhile, when one of the most notorious commodities traders in the industry is found hanging outside his office window of the 40th floor, Stella, Dr. Hawkes and Det. Flack are called to investigate. The apparent suicide is questioned when they learn the trader had one of the worst stock days in memory and a long list of clients with losses in the millions.