Tempus Magnus goes to 1898 London to try to stop Adam Worth from saving his daughter, which would alter the current time line.
Uprising Hollow Earth Abnormals amass at the surface with the Lotus Security Forces poised to take action as Magnus' people try to prevent an all-out war between humans and Abnormals.
Untouchable Magnus must explain a mission that went awry to a UN official as the Sanctuary faces scrutiny following the barely averted Abnormal uprising; Will's girlfriend turns up with an unforeseen problem.
Monsoon A hostage situation unfolds when Magnus flies to a remote island off of Africa to meet the Sanctuary's new financial adviser; a shipping container mix up has Will and Henry tracking a missing Abnormal.
Resistance The team tracks an Abnormal fugitive, and discovers that Tesla is the head of a secret research lab for a Homeland Security agency that conducts tests on Abnormals.
Homecoming Two flying Abnormals land on the Sanctuary seeking Magnus' help; Will is temporarily blinded during a riot in Monrovia.
Icebreaker Henry, Declan and a team from the UK Sanctuary go to the Bering Sea to investigate a mystery on a shipwrecked icebreaker, where the crew has killed the Abnormals on board and each other.
Fugue An Abnormal's attack on Abby leaves her requiring treatment at the Sanctuary while Henry and her FBI partner Gavin retrace her steps to determine what happened.
Chimera Adam Worth resurfaces as an avatar in a virtual Sanctuary, where he imperils Magnus and Tesla in a bid to enter the real world.
Acolyte Kate Freelander resurfaces with a warning about a Hollow Earth plot against an above-ground target, and evidence suggests that Bigfoot may be involved in the attack.
The Depths 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.
Sanctuary For None, Part 1 Caleb asks Magnus to help broker a peace deal between his insurgents and the governments on the surface; Addison reactivates Will's federal commission; Tesla resurfaces.
Sanctuary For None, Part 2 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.