Fear the Walking Dead: Who Is Grace?

Sunday's Fear the Walking Dead 502, "The Hurt That Will Happen," introduced newest series regular Grace (Karen David), a reactor worker with an expiration date tasked with taking out irradiated walkers.

"We wanted to show how difficult it was for our people to help out in the world, and Grace was someone that we thought of as a particular challenge for Morgan and Alicia and everyone else," co-showrunner Ian Goldberg told EW.

"At the end of episode 501 at that scene outside the truck stop, Morgan says, 'It should be hard. That's how we know we're on the right track.' Here in 502 we meet Grace, who we find out over the course of the episode is hunting down and killing the people who died as a result of the plant, the nuclear plant melting down, that she feels responsible for causing."

The melt down of a nearby pressurized water reactor left already dangerous walkers infected with contaminated particles, and Grace, a one-woman clean up crew, identifies the irradiated walkers through the use of dosimeters.

It's dangerous work — survivors who kill the marked walkers risk exposing themselves to radiation — and Grace, already exposed to soon-to-be lethal doses of it, turns down an offer to join newfound allies Morgan (Lennie James) and Alycia (Alicia Debnam-Carey) because she's needed elsewhere.

"She's someone who suffered exposure herself and feels that she doesn't have much time left. With the time she does have left, she thinks the only thing she can do to make up for her actions is to find and essentially take care of the people she cared about that she couldn't help when they were alive," Goldberg said of Grace's colleagues, a number that originally totaled 63.

"This is a huge challenge for Morgan and Alicia. How do you help someone like that who is at such a low point? That's going to be the challenge before Morgan and Alicia going forward. But also, is there any light at the end of the tunnel for Grace, or is this all there is for her?"

The concept of radioactive walkers proving harder-to-kill than standard walkers, already easily dispatched by the proficient group of survivors, is one the showrunners originally intended to tackle in Season 4.

"We just really didn't have the room for it, so it's something we kind of had in our back pocket that we were very excited about, and just having walkers that weren't as easy to kill," added co-showrunner Andrew Chambliss.

"Most of our characters are pretty proficient at killing walkers now, and the fact that there are now walkers out there that you can't kill in the regular way because if you get their blood on them you could potentially be exposed to contaminated particles, was something that got us really excited."