Watch the First Four Minutes of 'Defiance,' Episode 3 [Exclusive Video]

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Previously on "Defiance," Nolan (Grant Bowler) and Irisa (Stephanie Leonidas) not only settled in Defiance but became the town's law keepers. Nolan is now the chief lawkeeper, and Irisa is his deputy. The father-daughter duo are charged with protecting what used to be St. Louis before it was terraformed into an unrecognizable -- other than the Gateway Arch -- desert where the new settlement was built.

In this exclusive four-minute sneak peek at the third episode, "The Devil in the Dark," a human jogger readies his shiny new red sneakers for a peaceful jog in the woods. He takes off for his run -- just like he did on the Earth he remembered before the terraforming. How pleasant, right? Well, not quite. There are some nasty critters out there waiting for him.

[Related: 'Defiance' Is a Game-Changer … Literally]

The introduction of Votan animals and the mutation of all species on Earth resulting from terraformation have created something deadly. The poor jogger bites the dust, even after picking up the pace in hopes of escaping.

Meanwhile, Irisa is doing some tai chi-like moves, when she spots a butterfly on her blade. The butterfly is in perfect opposition to the knife-wielding personality that Irisa was born with, and that opposing personality is on display when a few of Irisa's own kind show up in Defiance.

A few Irathient bikers come to town for some sustenance and to terrorize the little Castithan children. It's easy to see where Irisa gets her fiery personality and the bright red hair to match. Perhaps she can finally make some new friends and feel at home in Defiance with her laid-back adoptive human father. On the other hand, Defiance is already filled with opposing personalities.

"The Devil in the Dark" airs on Monday, 4/29 at 9 PM on Syfy.