The 2nd Mass picks up the pieces after a devastating alien attack leaves Maggie fighting for her life…and Hal fighting for Maggie. Meanwhile, Tom and Dingaan are cut off from the rest of the group, buried under tons of rubble, where they must rely on an Enemy Ship to rescue them.

As the news of Sid’s death reverberates through the compound, the base begins cracking down on security on The Hill, which creates new complications for the scientists’ work. With all files and case studies on lockdown, Frank’s team is locked in an uphill battle to resolve the Implosion experiment without Sid’s expertise, leading Frank to resort to creative measures. Charlie grapples with unsettling feelings about his group. Abby starts a new chapter. An MP looks for penance for his actions.

Masters continues to break new ground by continuing his study as the only white physician in a Negro hospital but at the cost of his gynecology practice. Libby is confronted by Coral's boyfriend, Robert, over her poor treatment of Coral, Betty reunites with her former lover, and Johnson struggles to right her relationship with DePaul - who is newly aware of Johnson's ongoing affair with Masters.

Ray gets compromising information on Cochran. Avi follows Kate as she investigates, but Ray will need to give her a new story. Meanwhile, Abby tries to have fun with her prospective new neighbors, and gets closer to Jim, her cop friend. Marvin takes Bridget to a party at the house of ex-con/hip-hop mogul Cookie Brown. And Conor apologizes to Alex - but it doesn't go well.

With Chandler and Tex caught in a dangerous situation, Slattery has to step into the role as commanding officer. Torn between a mission with the fate of the world at stake and a Captain (and friend) in danger, Slattery has to find a way to get his people back without losing the most important asset: the vaccine prototype.

After learning his father has escaped the psychiatric hospital, Kevin orders an APB to track him down. Jill attempts to break an endurance record. Holed up in Indiana, a disillusioned Tom makes an unsettling discovery.

Vanessa has second thoughts about the lottery and consults Darius and the President about shifting the control back to the government. Darius and Vanessa discover the culprit behind the diplomat’s kidnapping and death while Alison and James quarantine Kyle as they dive further into the anomalies found in his blood.

With Nora gone, Eph reluctantly joins Setrakian's quest in hopes of gathering enough evidence to warrant a citywide quarantine. Fet encounters the unexpected inside the subway tunnels. A medical emergency threatens Palmer's master plan.

Freya relives one of her past lives with Killian. Dash does a spell at work without realizing the consequences. Joanna seeks the help of an old friend, Alex. Wendy and Freddie work together to try and stop the Mandragora while Ingrid’s bond with it grows stronger.