Spoilers for this episode.
Hidden inside Ontario Airport, Jack sends CTU photographs and information about the gunmen holding the terminal. Buchanan has found evidence supporting Jack's claim that he was framed, and Chloe is allowed back to work despite her arrest. The hostage leader Beresch demands cancellation of the treaty with Russia. Logan refuses to surrender the agreement, leaving Curtis to prepare a rescue while Jack watches the captives from above.
Beresch executes a hostage on camera and selects Derek as the next victim. Curtis cannot mount his assault before the threatened execution, so Jack asks Chloe to find a way to trigger one of the gunmen's explosive vests remotely. With Spenser's help, she gives Jack the signal he needs. He detonates a vest just before Beresch can shoot Derek, disrupting the terrorists and buying the boy more time.
Martha searches the retreat's archives for the written transcript of Palmer's call, obtaining a document that supports her memory. Cummings learns both that she has been searching and that Jack is assisting CTU from inside the terminal. He passes Jack's location and connection to Derek through Nathanson. Beresch jams Jack's phone, forcing Curtis to abandon the assault. When Beresch again threatens Derek, Jack leaves cover, puts down his gun and allows himself to be captured.