With a government inspector threatening to cut off the Sanctuary's funding, Magnus and Will must explain a mission gone wrong. Meanwhile, Henry has a surprise visitor with some shocking news.

Kate returns from Hollow Earth with word that insurgents are about to strike an above-ground target – and may have inside help from a trusted member of Team Sanctuary.

Magnus is approached by a notorious leader in Hollow Earth who is looking for assistance in building a new home on the surface for his insurgents, but problems arise when the world's government gets involved. Addison reactivates Will's federal commission.

With the new Abnormal Homeland now openly under threat, Henry and Tesla learn that the SCIU weaponized Tesla's work to use against Abnormals. Bigfoot and Kate investigate Caleb's rise to power while Will and Abby look into Magnus' past.