A man with an engagement ring turns up dead on the Brooklyn Bridge--but more than one woman could be the prospective fiancée. And a socialite dies in a penthouse with serious bruises and another man's blood on her body, and LSD in her system.

CSI investigates the deaths of a model stabbed by an ice dagger, and a marathon runner with frostbite marks on his face on one of the hottest days of the year.