Spoilers for this episode.
Jack and Curtis prepare to raid the nightclub identified by Prado. Audrey objects to the torture that produced the lead, and Logan responds to Jack's defiance by ordering his arrest. Jack sends a remote camera through the club's ventilation system while Marwan records a message about the planned nuclear attack. Secret Service agents arrive during the operation and insist on taking Jack into custody. The disruption exposes CTU's presence, giving Marwan time to escape through a tunnel.
Buchanan tells the White House that Logan's order compromised the mission. Logan loses confidence, and Novick calls former President David Palmer to ask for his help. Jack is released, but Marwan is gone. A separate lead comes from Sabir's girlfriend, Nabila, who has found suspicious material on his computer. Sabir is working with Morrison in Iowa to adapt the stolen warhead. Nabila's files contain a chip design connected to that work.
Chloe is sent to Nabila's house because she is the analyst best able to unlock the remaining data. She admits she is frightened of field work, and the visit turns dangerous when a gunman attacks and kills the escorting agents. Chloe and Nabila escape through a window and take shelter in the CTU vehicle without its keys. As the attacker rams the car, Curtis supplies the weapons-case combination. Chloe retrieves a rifle, gets out and shoots the gunman.