A Las Vegas team of forensic investigators are trained to solve criminal cases by scouring the crime scene, collecting irrefutable evidence and finding the missing pieces that solve the mystery.
Grissom, Catherine and Nick investigate the death of a runner during a competition. Meanwhile Sara and Warrick investigate the death of couple in a hotel room, initially thought to be a murder-suicide. Both cases take place during this 'cop' competition , with more than 20.000 attendants (all of them cops). This gives the investigations an interesting turn, as almost all the suspects and all dead people are cops.