 The brutal rape and subsequent death of a female motorist turns out to be an informant for the FBI acting as a cyber vigilante for catching on-line pedophiles to capture the predators. Stabler, along with the homicide detective who found the victim s husband murdered, follow the trail of evidence for the latest victim she had been tracking, leading them to the US Attorney s Office and a trip to Prague for Stabler to assist the Czech authorities when they find the kidnapped girl.