Iain Robertson plays Craig Stevenson
It's taken time, but finally Sea Of Souls research assistant Craig Stevenson has warmed to his newly-qualified colleague Justine McManus - but that's not to say the pair have stopped their sibling-like squabbling.
And according to actor Iain Robertson, their on-screen banter is mirrored by his off-screen friendship with co-star Dawn Steele.
"I think basically we are Craig and Justine in real life," he jokes.
"We don't go hunting for ghosts or anything like that, but our rapport is essentially just the same. We are two people who get on great, who have a laugh, but have the capacity to nip at each other at the slightest thing. It's definitely a very brother and sister like relationship.
"Craig and Justine are getting along much better this series, but it's good because they still have little niggles and digs at each other in much the same way that Dawn and I do," he reveals.
"Sometimes I think the guest artists must come in and think we don't like each other, because we can be sat in make-up bickering away and it must look quite odd.
"We just have a great camaraderie, I suppose. And Bill is great because on screen and off, he's like a father figure that hovers over both of us and breaks up the fights."
Craig's new friendship with Justine leads him to discover her hidden psychic skills, and it's a revelation that has far-reaching implications for him.
Not only does he come to feel protective of Justine, his discoveries also call into question the very beliefs Craig holds dear. Suddenly, for someone so self-confident, the world is a far less certain place, and the truth much more difficult to define.
"His eyes are opened to the possibilities of the paranormal world by what he experiences with Justine," explains Iain.
"He actually ends up being quite scared, because none of it fits in with his theories. It all deeply impacts on Craig and so there is a real change in him this series.
"He's still a bit cocksure, but he's slightly more mature and if he does put his foot in it, he at least tries to make amends."
While Craig's not quite the spiky know-it-all he once was, there is still a slight air of arrogance around him as he's prone to engage his mouth before his brain.
But whilst Craig embarks on an emotional journey in the six new episodes, Iain believes his character's conversion is in tune with a widespread acceptance of the paranormal.
"I think there is a shift in the psyche of people and more of us are open to the idea that the paranormal is possible.
"Personally I choose to believe in the paranormal, I'm hugely interested in it and I've been to various psychic events," reveals the Glaswegian actor.
"Coming from Scotland I grew up with lots of ghost and ghoulie stories, they were a big part of my childhood.
"But I suppose I first became really interested in the subject around the time when I lived in a flat that I was sure was haunted.
"While I was there I started having weird feelings and strange things began to happen. There was a room that was always cold, no matter what I did - I could leave a heater on in that room all day, it would still be freezing.
"Eventually, I looked into the history of the place and it transpired that certain things had gone on in that room in the past. I found it fascinating that a dramatic and traumatic event could leave such an imprint on a place all these years later."
While Iain's interest in the paranormal has been stirred by the series, he believes that some practices are best left alone.
"I would never take part in a séance, which is the focus of the opening episode. I think we are playing with fire if we get too involved in séances and the like, as they are something we still don't understand.
"If you don't understand electricity, you don't open up a fuse box do you? So if you don't know about something, don't go messing around with it, that's what I say."
This series also sees plenty of action sequences for Craig, much to Iain's delight.
"There's a lot more action this time around and, like most blokes, I always love the chance to run around and pretend to be Indiana Jones saving the world.
"In one episode I had to do a car chase, then I found myself kicking a door down, having a fight and smacking a mirror over someone's head," smirks Iain.
"The new episodes were really exciting to film. They are very scary and full of tension, but at the same time there's room for wit.
"The scripts are fantastic, I really enjoyed reading them and I wasn't even thinking of them within a work context – they were just thrilling to read, which is always a good sign. It's so good to be in a show that I'd want to watch as well."
In between series the young actor - who has also starred in Band Of Brothers, Oliver Twist and Small Faces - found time to squeeze in a film role in the big screen sequel Basic Instinct 2: Risk Addiction, alongside Hollywood superstar Sharon Stone.
"It was great to work on a big budget movie like that - although my pay packet wasn't big budget at all," he jokes.
"I didn't get to see much of the lady in question as I was mainly working with David Morrissey, who is a brilliant actor. So that was a real experience."
And as Iain reveals, his Basic Instinct character was inspired by real-life encounters throughout his acting career:
"I play a sleazy journalist which was good fun, as over the years I have met a few people who have definitely inspired my interpretation of the role," he jokes.