23. Firewall

Complete story — includes the ending

Fusco is hired by HR leadership to obstruct any investigation into a planned murder, with the target being the latest POI: Dr. Caroline Turing, a therapist with a powerful client list. Reese poses as one of her clients and saves her from an assassination attempt. HR and FBI later converge on the hotel where Reese is hiding Turing; Carter and Fusco help them escape and fend off HR – discovering in the process that they are on the same side – while Finch waits in a car to collect Turing. However, he is met by Corwin, who demands his help in shutting down the Machine. Corwin is suddenly shot dead by Turing, who reveals herself as "Root," the mysterious hacker Finch previously encountered. Root anonymously hired HR to target her, thereby putting her on the Machine's radar and allowing her to learn more about it. She abducts Finch before Reese can arrive. Fusco sends evidence to the FBI allowing them to arrest an HR mole and exposing HR's Inner Council, the first step towards bringing the organization down. Reese asks the Machine via a surveillance camera to help him find Finch. A payphone rings nearby and Reese answers.