Jimmy Brooks

Danny and Maria investigate when an expectant mother is a victim of a "knockout game," in which teenagers punch unsuspecting civilians in the head. Meanwhile, Frank wrestles with promoting an officer when he thinks it can be viewed as favoritism.

Holmes and Watson race to help Detective Bell when he becomes a victim of a bio-terrorism attack at the precinct and the station is quarantined. During the lockdown, Captain Gregson and Detective Bell begin to suspect they are trapped inside with the perpetrator. Also, Watson faces the difficult task of helping her mother, Mary (Freda Foh Shen), accept that her advancing Alzheimer’s disease requires her to receive more medical care.

In the aftermath of a deadly attack on the White House, Elizabeth tries to keep a major nuclear disarmament deal from falling apart while a manhunt for the attackers brings D.C. to a halt. For advice, Elizabeth turns to former secretaries of state (guest starring as themselves) Madeleine Albright, Hillary Clinton and Colin Powell, on the fifth season premiere.

Elizabeth and cabinet members brace for the fallout at home and abroad as President Dalton prepares for a retaliatory nuclear attack on a country that has reportedly just launched missiles bound for the U.S. (TV-14 L)

Elizabeth is attending a summit in Montreal to resolve territorial claims of the North Pole when an activist group detonates a bomb and she can't locate Jason and Piper. Also, things take a turn for the worse when Elizabeth learns that Russia was involved in the bombing, and Henry helps one of his students work through a difficult decision.