The episode opened with the CSI team looking for DB and Catherine after both disappeared. They eventually find DB’s car abandoned near a call he was supposed to have been at. With the help of a friend (Ms. Kitty and Jack) DB and Catherine managed to avoid the hit squad and come into the lab safely.
Looking at the evidence DB, Catherine, and the team concluded that it appeared that crack hit squad were leaving to much evidence and determined they might not have been sent Mark Gabriel after all. Some double checking of the evidence finds that the two bodies that were believed to be Laura and McQuaid were not them after all.
After they explained that Laura and McQuaid were behind it to Gabriel, he convinced the hit man to take out Laura and CSI followed the money and the directions to find Laura held up in a house. The hitman then told them that they already had McQuaid that he was the dead body they found earlier in the day.
When all was said and done, Catherine accepted a job with the FBI and said goodbye to the CSI Team.