A mugger is found dead on the street, his neck broken. But Horatio's team has a bigger problem on their hands as during the autopsy, Alexx and Horatio realize the man was exposed to radiation. Now the team must race against time to find the man's killer before the next victim, an environmental lawyer, dies from radiation poisoning

Before Horatio is set to testify at a murder case in which the defendant is the husband of a city councilwoman, he's given new facts that could prove the man is innocent. There is also new information which revolves around the discovery of a second victim who would match the alleged killer's profile - if the man on trial isn't guilty.