Blindspot: Jane Gets Some Fatally Bad News in This Exclusive Season 4 Premiere Sneak Peek

Jane Doe (Jaimie Alexander) is in a dark place as Season 4 of Blindspot begins. She's evil Remi Briggs again and secretly working to carry out terrorist org Sandstorm's objectives in secret from inside the FBI, and she wants to kill Weller (Sullivan Stapleton) for what he did to her family. But it gets worse: the memory eraser that Shepherd (Michelle Hurd) and Roman (Luke Mitchell) dosed her with before Roman died that caused Jane to backslide into being Remi is slowly killing her, she finds out in this exclusive clip of from "Hella Duplicitous," the Season 4 premiere.

Reade (Rob Brown), Patterson (Ashley Johnson) and Rich Dotcom (Ennis Esmer) explain that the ZIP she was injected with never fully left her system, and the closer it gets to her brainstem, the worse her symptoms will become, including disturbing side effects we'll find out about later in the episode. It's further along than anyone realizes. Once it reaches her brain, her body will forget how to operate and will cease all involuntary function.

There is hope, though. Roman was going through the same thing from his own injection, since he and Shepherd didn't realize the ZIP was so dangerous, and the cache of data he gave Jane before he died contains theories on cures. Emphasis on "theories."

So Remi has a lot of clocks ticking now. She has to accomplish her objectives before she's discovered, and she has to either find a cure for her poisoning or die trying.

There's no good option here. Hopefully the cure will restore her to sanity as well as save her body.

Blindspot Season 4 premieres Friday, October 12 at 8/7c on NBC.