Jack and Lynn must take action when they discover that the nerve gas is breaking through the protective seals that are keeping the CTU survivors alive.

Chloe wrestles with her grief over Edgar's death, while Tony contemplates revenge against Henderson.

Martha bolster's Logan's spirit as he wavers under more political pressure from Gardner.

Jack bargains with a German intelligence agent in order to find the woman who can lead him to Bierko.

Buchanan chafes against the new chain of command as Homeland Security prepares to take over CTU operations.

Aaron receives a request for a secret meeting from Wayne Palmer, as Logan implements martial law in L.A.

Jack pushes Audrey for answers when evidence indicates that she may be involved with the terrorists.

Wayne and Aaron flee from a group of gunmen who have orders from Henderson to kill them.

Bierko and his men gain access to a natural gas plant, where they plan to distribute the nerve gas throughout L.A.