“I have to be careful not to reveal too much,” Capaldi said when asked who Gideon was. “In some ways, he’s a criminal. He’s a murderer and a threat to society. So he’s a very, very smart and elusive villain that the police are pursuing (and never quite managing to catch). Until they do.”

Capaldi added that, once Gideon is caught, things take a drastic turn. “He then reveals that he’s not quite what we think he is,” he said.

As well as Capaldi’s Gideon, the series also centres on Jessica Raine’s character Lucy, who is woken every night at 3:33am (the devil’s hour) by terrifying visions, and whose house appears to be haunted.

How the pair’s lives connect is unclear at this stage, but we luckily don’t have much longer to find out.