Polaris' baby begins to suffer from a deadly illness, leaving the Inner Circle unable to heal her, and prompting them to turn to an unexpected source for help. Meanwhile, Reed and Lauren take an excursion to deliver illegal meds, but Reed's powers complicate their plans. Then, Thunderbird and Blink meet the leader of the Morlocks - a shadowy group of mutants that live underground - who offers to help them find the Inner Circle, but the two factions may not have the same goals.

As Caitlin and Thunderbird struggle to save the life of a mutant injured in the Inner Circle's chaotic liberation of a psychiatric hospital, they discover clues to the identity of the powerful mutant Polaris and Andy were sent to retrieve. Meanwhile, as Jace joins up with the Purifiers to chase down the escaped mutants, he comes dangerously close to colliding once again with the Mutant Underground.

Reed worries as Lauren becomes intrigued by her ancestors and their violent powers. Lorna begins to reevaluate her trust in the Inner Circle after figuring out the past of Reeva's new trainees. Meanwhile, Benedict Ryan continues to encourage Jace to take action with the Purifiers. Marcos asks Clarice to go to the Morlocks in search of information on the Inner Circle and Thunderbird gets a call from Evangeline.

With the Inner Circle and the Purifiers on the rise, and the nation more divided than ever, the dream of the X-Men is on the verge of failure. In attempts to revive the Mutant Underground, Evangeline proposes a country-wide meeting. Meanwhile, Lauren and Andy continue to disagree in their dreams and the Frost Sisters attempt to intervene. Caitlin makes the risky suggestion of connecting with a family member for vital intel, and Lorna tries to secretly investigate Reeva's plans for the Inner Circle.

Lauren stops sleeping so she can avoid the forces in her dreams pushing her towards joining Andy and giving in to her dark side. Glow is in trouble after being shot by the Purifiers, and Blink convinces the Morlocks to let Caitlin save Glow. Meanwhile, Polaris learns the details of what Reeva is planning, and Reed helps Lauren fight off her dreams.

When one of the Inner Circle goes missing, Reeva intensifies security in their compound, but realizes that her plans may have already been exposed. Furious and paranoid, Reeva resorts to violence. Caitlin and Reed consider using the serum to restrict Lauren's use of her powers, hoping it will help her as she wrestles with nightmares about the Inner Circle and her ancestors. And it's the battle of two extreme ideologies when the Morlocks and the Purifiers come face-to-face in battle.

Lauren can't access her powers when it matters most, leaving Caitlin to take matters into her own hands when they are being pursued. Reeva finally reveals her plan for the Inner Circle and it's darker than anyone could have imagined. Meanwhile, Jace confronts some regrets about his actions and is torn between pressures from the Purifiers and his own beliefs.

Reeva prepares to carry out her plan for the Inner Circle, but not everyone is on the same page. Reed struggles to manage his powers and the family realizes that without enough of the serum, it's only a matter of time before he completely loses control. Frustrated and egged on by Benedict Ryan, Jace and the Purifiers are on the attack, but for Jace, things aren't as black and white as they once were.