Its story, somewhat familiarly to those who know the zombie genre, began several years into a "zombie apocalypse" – typically, a virus outbreak that transforms part of the population into flesh-eating monsters – and focused on Murphy (Keith Allan), a so-called "patient zero", who, because of an experiment being carried out at the time, was unaffected by the virus.

The second season picks up where the first left off, with the launch of nuclear weapons. "All the nukes are coming down," Schaefer says. "We'll see what happens, and who survives, and who doesn't make it. And what happens to the world out there."

The series, perhaps like many in the genre now, has never shied away from killing apparently major characters. Schaefer says that's simply what is expected in modern storytelling. The years where main characters were insulated from risk because of their perceived star power is largely gone.

"Just to keep the audience on edge and to have some credibility with them," he says. "If we never kill any of our main characters, then that sort of takes the drama out of those intense scenes. It's when we sort of go beyond those boundaries ... in episode two of this season it's a fight from minute one through the whole thing.

"It doesn't turn out well," he adds. "But, at the same time, that's what makes the show exciting, and different, and how you'll tune in, and not know what's going to happen this week. We want the audience having to pay attention because they never know what's coming next."