28 Years Later: The Bone Temple star Ralph Fiennes says Dr. Kelson is on a collision course with Jimmy Crystal "It's good and evil, isn't it?"

Of the many surprises in 28 Years Later, few would have expected Ralph Fiennes' iodine-drenched, ossuary dweller Dr. Kelson to be the film's tender heart and soul. But Dr. Kelson's good man is set to meet his match in Jack O'Connell's psychopathic Jimmy Crystal when sequel The Bone Temple hits screens.

Picking up the story of Alfie Williams' Spike, who was rescued/captured (depending on how you look at it) by the Jimmys in spectacularly strange fashion at the climax of 28 Years..., The Bone Temple follows Spike's horrific time among the Jimmys, in parallel to Dr. Kelson's surprising experiments on Alpha-infected Samson (Chi Lewis-Parry). But as the two storylines converge, a battle of good and evil awaits.

"It's basically that old one, primal," Fiennes tells GamesRadar+ during a conversation in London. "Kelson's a good man. He's a doctor. There's no twist in his psyche. He's eccentric, and he's accepting of death as a reality, but Jimmy is… well, it's clear quite early on that he has very profound psychopathic tendencies. But also, I think, for most people that disturbed, it's a childhood trauma that pushes them into sadistic behavior. But yeah, he's a nut job!"

As teased by the film's evocative poster, Dr. Kelson is also at the center of The Bone Temple's most surprising sequence – a ritualistic dance to a blaring Iron Maiden track. "That was great," Fiennes says. "We choreographed it and worked on it a lot with Shel[ley Maxwell], the choreographer, and Nia [DaCosta, director]. I even got in shape for it. And that Iron Maiden track is so amazing… that was the spice to get me motivated, was that incredible music."

Whether Dr. Kelson, Jimmy Crystal, Spike, and co. will feature in the recently confirmed third movie in the 28 Years Later trilogy remains to be seen, but we do know that Cillian Murphy's Jim will return after Danny Boyle let the news slip last year. The Bone Temple director Nia DaCosta also revealed to GamesRadar+ that there'll be no backflipping in the brutal new movie.

28 Years Later: The Bone Temple releases in US theaters on January 15, and in UK cinemas on January 13. For more, check out our list of the best upcoming horror movies to add to your watchlist.