With time running out to save the victims of a kidnapping ring before they are transported overseas, Jane and Lisbon zero in on the criminal enterprise’s mastermind. Meanwhile, Lisbon decides if she will move to D.C. with Agent Pike.

Sarah comes home looking for answers, and with the help of Cosima, they begin digging into the origins of the clone experiment. The hunt for answers takes her right into the belly of the beast, but getting out could cost her more than she knows.

Holmes and Watson come into contact with MI-6, the British intelligence agency, when a standard murder investigation turns out to have international and political implications. Meanwhile, in the wake of a crisis, Watson reevaluates her relationships with Sherlock and his brother, Mycroft.

Clarke and Bellamy go on a mission to find supplies for approaching winter. Some of the 100 accidentally eat nuts with powerfully hallucinogenic properties and lose their grasp on reality. Meanwhile, Octavia seizes the opportunity to help a friend escape, and a terrifying event brings Clarke and Bellamy closer. On the Ark, Commander Shumway secretly assigns one of the 100 to kill one of his own, and the treacherous actions of Diane Sydney are revealed.

Jay, Gloria and Manny challenge one another to try something new; Mitch and Cam sell a couple of their prized possessions to fund the wedding; the kids play a joke on Phil and Claire.

Oliver rallies his team as Slade’s soldiers attack the city. Felicity gets a call from S.T.A.R. Labs with game-changing news and Thea comes face-to-face with her father — Malcolm Merlyn.

Frankie limits the hours during which the kids can voice their needs; Mike watches to make sure Darrin doesn’t take advantage of Sue; Brick invites new friends over.

Truman, empowered with new authority from the President, launches a mustard gas attack designed to kill Miles and Monroe. To Rachel’s disappointment, Miles agrees to join Monroe in a ruthless plot to beat the Patriots at their own game. As Neville faces his own challenge from the Patriots, Aaron grows increasingly alarmed by the power of the nanotech.

Ward’s betrayal and Hydra’s shocking secrets are revealed as Coulson’s team goes undercover on a mission that leaves no one unscathed.

A secret investigation conducted by Beckett related to her mother’s murder goes awry when a man she has been surveilling is killed. When evidence links Beckett to the victim, she and Castle become the targets of a manhunt that puts both of them in grave danger.