Chuck investigates after a murder takes place in Castle; Awesome is alarmed by Ellie's new hobby; Morgan's leadership is tested.

Chuck and Sarah suspect Casey is carrying out private missions; Chuck fears the CIA's new operatives will render him obsolete; Morgan settles in with a new roommate; Awesome becomes uncomfortable with Ellie's research.

Chuck encourages Vivian (Lauren Cohan) to get in touch with her inner villain for a mission; Morgan's search for a new roommate has unexpected results.

The team is sent to England to protect a reclusive heiress; Casey gets an offer from Jane Bentley (Robin Givens); Ellie and Awesome solve a parenting problem; Morgan considers a move.

After Chuck reunites Sarah with her former spy team, old grudges and secrets are revealed; Morgan fends off the advances of a former flame.

Casey, Chuck and Sarah are sent to Morocco to rescue Roan Montgomery (John Larroquette); Morgan plans to meet Alex's mother; Mary spends some time with her family.

While Sarah tries to free Chuck's mother, Morgan and Chuck go after Volkoff; Casey and Alex bond; Ellie hopes to ease Awesome's anxiety over becoming a father.

Chuck worries about Sarah when she tries to help Mary Bartowski (Linda Hamilton) take down Volkoff (Timothy Dalton); Awesome and Ellie struggle to choose a baby name.

Chuck, Sarah, Casey and Morgan must stop Dr. Stanley (Robert Englund) from releasing a toxin that induces nightmares; Chuck's mother's allegiances are questioned; Lester and Jeff celebrate Halloween at the Buy More.

Chuck must decide what he is willing to sacrifice to find his mother; Morgan reveals a potentially dangerous secret to Casey.

Chuck and Sarah try to become better communicators as they join Ellie and Awesome on a trip to Costa Gravas; a forbidden romance may put Morgan at odds with Col. John Casey.

A prison transfer delivers old foes the Buy More, canceling Chuck and Sarah's romantic mission; Morgan gets a surprise from Big Mike.

Chuck and Sarah go under cover in Milan during Fashion Week to retrieve a high-tech secret weapon; Morgan discovers a fatal flaw that compromises the new Buy More.

Chuck and Morgan search the globe for Chuck's mother (Linda Hamilton); Casey and Sarah track an operative (Dolph Lundgren) of the mysterious Volkoff Industries; Ellie shares big news.