In order to prevent him from altering - or destroying - the future, Magnus uses Adam Worth's time portal to pursue him to 1898 London.

As Abnormals continue to "invade" the surface, Will, Kate and the Big Guy seek to prevent all-out war with the Lotus Security Forces - while worrying about Magnus, who was last seen heading towards Praxis just before it was destroyed.

Team Sanctuary comes under fire from a U.N. inspector who threatens to cut off their funding and shut them down - attempting to turn Will against Magnus in the process. Meanwhile, Erika visits Henry, warning him of a potentially dangerous new dilemma.

Intending to meet with her mysterious new financial adviser, Magnus flies off to a remote African island - only to become embroiled in a dangerous hostage situation. Meanwhile, back at the fort, Will and Henry have their hands full tracking an escaped Steno.

Magnus and Henry attempt to infiltrate a secret Abnormal testing facility run by Homeland Security and encounter an old friend whose loyalties are once again in question - Nikola Tesla.

Magnus gets tied up in an Abnormal scheme and Will runs into trouble at the Liberian Sanctuary.

When a team from the UK Sanctuary gets in trouble on a stranded icebreaker in the Bering Sea, Magnus and Will must figure out who is behind the mysterious happenings at sea.

A mysterious abnormal attacks Abby, and Magnus and Will discover there's only one way to communicate with this unusual enemy - through music.

Just when Magnus thought Adam Worth was gone forever, she and Tesla become trapped in a virtual Sanctuary, where they are attacked by an avatar of Worth - who is determined to enter the "real" world.

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.

A quest to capture a legendary Abnormal in Bolivia leaves Will and Magnus injured and trapped in a cave-in, where they confront truths about themselves and their relationship. Henry records video letters to a special someone while working on an invention.

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.