Finch goes undercover at a 911 call center to protect the newest POI, a 911 operator and trainee supervisor named Sandra Nicholson. Finch listens in as she takes a call from a young boy named Aaron, who is then taken hostage by a mysterious man who threatens to kill Aaron if Sandra does not delete the previous day's 911 call log - over 30,000 emergency calls. The man on the phone turns out to be thorough and very guarded, routing his call through multiple phone relays and using hired Templarios - kidnappers for Mexican cartels - to handle Aaron's abduction. Finch realizes that the kidnapper has planted a small camera on Sandra's headset that allows him to track her every move, so he's forced to help her through this ordeal without ever holding a face-to-face conversation. Thinking that the man on the phone is trying to delete a specific call, Finch enlists Fusco's help to scan through the previous day's relevant calls, hoping to find clues as to who the mysterious man might be. Fusco finds a call that links up with a murder case he's working on and determines that the people who killed his murder victim hired the mysterious kidnapper to cover their tracks. Reese and Shaw fight their way through a host of Templarios to rescue Aaron, but they never get close enough to the mystery man on the phone to determine his identity.