Outlander's Roger and Brianna's marriage threatened in season 6

The young couple first met in 1960s Scotland, when Brianna learned the shocking truth from her mother Claire (Caitriona Balfe) that her biological father was actually an 18th century Highlander named Jamie Fraser (Sam Heughan).

After travelling back into the past, where they enjoyed a romantic engagement, locked horns and experienced a series of tragic misunderstandings, Roger and Brianna were separated again when Roger was assaulted and sold to the Mohawk by Jamie and Brianna’s cousin Ian (John Bell), while a pregnant Brianna waited in vain for his return.

Even once the pair were happily married and raising their son Jemmy, there remained a frostiness between Roger and his new father-in-law Jamie – the former resentful that Jamie had attacked him, the latter unsure that he was good enough for Brianna.

But their relationship gradually unthawed in season 5 and in the final episode, we saw Roger and Brianna attempt to travel "home" through the stones, only to wind up back on the Ridge with Jamie and Claire.

What will happen to Brianna and Roger in Outlander season 6?

In season 6, there's “a real strength” to the combined family, revealed Rankin in an interview with RadioTimes.com.

"They are certainly unified," he added. "I don’t think there are these questions hanging over them of 'Will or won't Roger and Brianna go back through the stones?' Does or doesn't Jamie like Roger?' Those questions have kind of resolved themselves in season 5.

"So it gives us a really strong platform to take on the external factors in season 6, like the community and [new family] the Christies arriving, the Revolutionary War, the aftermath of what happened in season 5 [when Claire was abducted and assaulted].

"I think that Jamie found the respect for Roger. There was a lot of misunderstanding between the two of them from the off, but he's seen him in the light of what he is and has a respect and admiration for Roger, which will presumably continue from here on in."

Instead, a new issue for Roger and Bree to contend with is his relationship with a young widow Amy McCallum (Joanne Thomson) and her children, who have also come to settle on the Ridge.

In Diana Gabaldon’s sixth novel, A Breath of Snow and Ashes, Roger spends a lot of time helping the struggling McCallums – but that leads to rumours that there is an illicit relationship between him and Amy.

Rankin joked about Roger's maddening naivety when it comes to Amy and how her presence will impact his marriage: "I don't see what's wrong with meandering off to the neighbouring single woman's house for the afternoon and evening, eating there, potentially then Roger goes back home and Brianna says, 'I’ve made dinner or do you want dinner or shall we get a takeaway?' and Roger says, 'Oh actually, you know what, I’ve already eaten at this woman’s house down the street. Don't worry though! She's a widow. It's fine. I'm going to go back there in the morning if it's OK to fix her chimney?'"

Skelton chimed in: "'I haven't bathed Jemmy tonight but I've bathed her kids, so it's all good.'"

Rankin continued: "'Yeah, I’ve been looking after them fabulously and reading them bedtime stories.' I can't see why Brianna gets annoyed with him to be honest!"

And since season 6 of Outlander will also see Brianna using her engineering skills to make matches? "Don't mess with Bree – she's got white phosphorus!" laughed Skelton.

Rankin agreed: "She will literally blow you up."

Outlander is available to watch on Starz US now. Check out our Drama hub for more news, interviews and features or find something to watch with our TV guide.

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