Naomie Harris Photo: IC

Jude Law Photo: AFP

The Third Day, a new mini-series starring Jude Law, is pushing the boundaries with a daring set-up: a different lead actor for each half, and a live 12-hour episode in the middle.

The series, which also stars Naomie Harris, premieres Monday on US cable network HBO. The psychological thriller is co-produced by Britain's Sky Studios.

The action takes place on Osea Island, a secluded holiday spot east of London in southeast England. Sam (Law), a 40-something with a dark family secret, finds himself stuck on the island, not knowing the trip will change his life.

After three "Summer" episodes that see Sam become increasingly unmoored, the second "Winter" part of the series stars Harris as Helen, a single mother who comes to Osea to celebrate the birthday of one of her two daughters.

Helen is seemingly absent from the first half of the series, while Sam disappears from the second half.

But the creators of the series decided to push the envelope with "Fall," an uninterrupted 12-hour live episode, airing on October 3. They have revealed little about how it may link the two halves.

The audacious project is being carried out in collaboration with the British theater troupe Punchdrunk, which is known for its interactive works such as Sleep No More, which puts audience members at the center of the action.

"In the same way we broke the rules of theater with our shows, I was curious about how we could break the rules of television," Punchdrunk founder Felix Barrett told a virtual roundtable chat held for the Toronto film festival.

"What happens when the fourth walls, the screen we're watching, collapses in front of us and actually audiences are able to fall inside the world of that TV. What's the liminal space between the real and the fictional," he said.

"This is an amazing sort of space for the audience to be when they're questioning the validity of everything."

In the filmed episodes, The Third Day relies on the talent of its stars, who infuse the material with gravitas and an eerie mood. Edgy music, halting camera work and lighting tricks add to the drama.

Law called the experience an "emotionally exhausting marathon, really, which nearly killed me."

The actor said the writing of the main scribe, Dennis Kelly, is "so extraordinary because it delves into dark places, uncomfortable situations and interactions, but it does it with this extraordinary brushstroke of humanity and humor."

"It takes you to places that cost and I would say that that's possibly the experience that people will have watching it," Law added.