'28 Years Later' star Jodie Comer on her character's personal hell

There are several circles of hell within 28 Years Later, from exterior threats to private pain.

The latter is where Jodie Comer's character, Isla, lives for the duration of Danny Boyle and Alex Garland's latest instalment of the zombie horror franchise, a woman whose illness has gone undiagnosed with the demise of doctors in the Rage Virus-ridden UK. While her son Spike (Alfie Williams) and husband Jamie (Aaron Taylor-Johnson) are all too aware of the dangers surrounding them, Isla seems to live on a different plane of reality through episodes of paranoia, delirium, and confusion.

"She does have her own inner turmoil, but it's also a place where she can kind of escape," Comer told Mashable. "She has this weird naiveté for a lot of the time about the dangers and the severity of the situation, which Spike and Jamie aren't afforded."

The family unit of Jamie, Isla, and Spike lies at the heart of the film, with the story divided equally into exploration of fatherhood and motherhood during a 12-year-old boy's coming of age in a zombie apocalypse. But within this family, things are more than strained, with Jamie dealing with loneliness while caring for his wife, Isla slowly disconnecting with reality through immense pain, and Alfie forced into a parent role at a young age.

"It was an interesting thing for me and Alfie to find in the nuance of that dynamic of like, OK, here's your mum but actually you, 90 percent of the time, are having to be the parent, and having to guide and nurture and comfort, when there's a young boy there who actually that's what he needs from his mum," said Comer.

"It was a dynamic that felt unfamiliar to the both of us, I think. And we were lucky because we had two weeks of rehearsal before we started where we could all get together and establish a history."

Family, found or otherwise, has long anchored the franchise, from the devastating duo of taxi driver Frank (Brendan Gleeson) and his daughter Hannah (Megan Burns) in 28 Days Later to Don (Robert Carlyle) trying to reconnect with his family in 28 Weeks Later. So, Boyle and Garland naturally carried this thread through to the 28 Years Later.

"I think it mirrors the original, I think that's what Danny and Alex do so beautifully," said Comer. "It's like yes, this is a horror genre but then it's so intimate and really about human connection and how we deal when we're faced with adversity, and relationships and emotion, and all that tactile stuff which we can all relate to because we experience it within our own lives. They somehow marry it all together so seamlessly."

28 Years Later is out now in cinemas.