What is wrong with Isla in 28 Years Later? Explained

28 Years Later answers the headline in plain terms: Isla is not infected. She has terminal brain cancer. From the Holy Island prologue, 28 Years Later shows memory gaps, piercing headaches, and sudden mood swings that unsettle her family and community.

The boy, Spike, pushes a mainland run to find Dr. Ian Kelson, a rumored doctor. Midway through 28 Years Later, Kelson examines Isla and explains that there is no cure. He offers care and clarity instead. 

In 28 Years Later, Jodie Comer is Isla, Aaron Taylor-Johnson is Jamie, and Alfie Williams is their son Spike. Ralph Fiennes portrays Dr. Ian Kelson, Jack O’Connell plays Sir Jimmy Crystal, Chi Lewis-Parry is the Alpha called Samson, and Edvin Ryding appears as Erik Sundqvist.

On the rails, 28 Years Later stages a key reveal when Isla helps an infected woman deliver a baby who is not infected. The scene reframes the mission around biology and care rather than a “turn.”

Later in 28 Years Later, Isla chooses euthanasia, and Kelson guides a peaceful death. Spike places her remains in Kelson’s ossuary, names the newborn “Isla,” and returns the child to the island. In the final beat, 28 Years Later sets the path toward 28 Years Later: The Bone Temple, with Spike stepping into a new human threat on the mainland.

What is wrong with Spike’s mom in 28 Years Later?

On Holy Island, 28 Years Later shows Isla forgetting recent conversations, flinching through sharp headaches, and wavering between calm and confusion. Spike’s aim is simple: reach a doctor who might explain what the island gossip cannot.

After the “first-kill” rite, the boy’s motive tightens. His trip is for his mother, not bravado. In a quiet fireside memory that underscores her decline, Isla tries to hold on to family details. Isla in the movie remarked,

“Your granddad was so silly, and everyone else thought he was so serious, but round me, he was daft. You know, when I look in your face, I see your granddad's eyes. It's nice.”

It's a line that plays as tenderness and as a sign of slipping recall.

Train birth, Kelson’s exam and the diagnosis: How the film shows it’s cancer, not contagion

The train sequence anchors the middle of 28 Years Later. Isla hears a scream, finds a pregnant infected, and midwifes a birth. The baby is uninfected, which points the story away from Isla “turning” and toward medical reality. The pair then reach Kelson’s sanctuary of bones, where he studies Isla and identifies terminal brain cancer. The focus becomes comfort, dignity, and meaning. Kelson frames the theme in direct speech. Dr. Kelson, played by Ralph Fiennes, said,

“Do you know the words memento mori?”

and then stated,

“It means remember death. Remember you must die.”

He later reiterated to Spike,

“Memento Amoris "

The Latin phrase translates as "Remember, you must love". These lines set the lens for every scene that follows, including the way Spike carries his mother’s memory and the newborn’s future.

Isla’s choice and legacy: Euthanasia, the bone temple, and the road Spike walks next

Late in 28 Years Later, Kelson facilitates a peaceful death after explaining Isla’s condition and the limits of care. Spike helps place her remains in the bone temple, then brings the baby, now named Isla, back to Holy Island with a note that confirms her uninfected birth. He does not stay.

28 Years Later closes with Spike moving into the mainland’s new human danger, a transition that positions the sequel 28 Years Later: The Bone Temple.

The film ties Isla’s arc to simple acts: choosing the time of her death, honoring the dead, and protecting a newborn who arrived free of the virus. Kelson quietly contextualized his shrine:

“And so many dead. Every skull is a set of thoughts. This is a monument to them.”

The meaning carries forward as Spike accepts loss and steps into what comes next.

Stay tuned for more updates.