Writing power couple Graeme Simsion (The Rosie Project) and Anne Buist (the Natalie King crime novels) planned everything meticulously.

The keen walkers had already twice conquered the world-famous Camino de Santiago pilgrims’ route through France towards northern Spain, drawing from their travels the gist and inspiration for their best-selling novel Two Steps Forward.

Detailing the halting dance of recently widowed American Zoe and Martin, a freshly divorced Brit, the novel was a refreshing take on autumnal love.

So what could possibly go wrong with the sequel, Two Steps Onward?

Even before they  left Australia, Simsion and Buist plotted their latest trek along roads less travelled – the Chemin d’Assise and Via Francigena through Italy towards Rome – while figuring out what might happen between Zoe and Martin and the big question mark over the fictional couple’s chances of  happily-ever-aftering.

By the time they got to the Italian capital, taking plenty of notes to flush out the finer details of the new book, it was early March 2020, COVID-19 was everywhere and the world was in the process of falling apart.

“We were sitting in Rome saying, ‘Get me on that plane’,” Buist said, recalling the surreal shadow the virus cast over what had been another spectacular adventure together.

“We tend not to do much on our phones while we’re walking, other than occasional check-ins with the kids, so I didn’t really look at the news until we hit Rome, and then we realised that Lombardy was a disaster.”

It had become one of the epicentres of the unfolding pandemic that was ravaging and raging its way around the world.

“Italy was in a terrible way,” Simsion recalled. “But there was very little recognition of that in Rome. Nobody was wearing masks, and it was very relaxed at the airport.”

By the time they reached the midway point home, Dubai, it was a very different situation.

“It was only then that it hit us,” he said.

They made it back to Australia just before international borders slammed shut.

Melbourne’s extended lockdown last year became a forced period of focus on editing the novel, and their myriad solo projects, with Buist also holding down her part-time psychiatry gig.

If you thought the first book would naturally lead to enduring bliss, well, it didn’t quite work out like that.

“They teach you that the one rule of romantic comedy is that romantic love has to be the highest value,” Simsion says, noting that both he and Buist agree that doesn’t quite work for older protagonists encumbered with rusted-on commitments.

When we re-join them in Two Steps Onward, the whirlwind romance has drifted away. Zoe decided to focus on her career in San Francisco, and Martin on his troubled daughter back in the UK.

But Zoe is pulled back to the provincial French town of Cluny by the news that her friend, Camille, is deeply unwell, and they plan to walk together to Rome.Though Martin is initially reluctant to join them, of course that’s exactly what he ends up doing, and Two Steps Onward focuses on a different sort of ‘will they, won’t they’ story.

“We also knew there weren’t going to be as many people on this walk, unlike the Camino where there’s lots to bump into,” Buist said of the fictional trio’s trek.

“We only saw two or three pilgrims at the most, and they were only doing two-week sections. So we knew there had to be a different dynamic. We didn’t want to just do the same old, same old.”

What unfolds is a much more intimate navigation of romantic love, friendly and familial, with a smaller coterie of characters but just as much heart.

“The geography of the walk shaped it,” Buist added.

“The Alps were exhausting, so that ended up being one of Zoe’s low points, but then she and Martin end up cuddling, and Italy is going to be fabulous.”

Plans to bring The Rosie Project and Two Steps Forward to the big screen, are stalled for now, as is a planned trip to the Japanese island of Shikoku, for obvious reasons.

But Buist and Simsion did go on an extended trip around Australia in a four-wheel-drive, camping as they went, with only a minor diversion due to a cyclone in the Northern Territory.

Don’t expect a third book to have Zoe and Martin head Down Under, though.

“That territory’s been well and truly covered, and covered pretty well,” Simsion chuckled.

“We also don’t write much when we’re travelling. It’s an idea that we think should work, but doesn’t.”

After the year we’ve had, it’s a wonder anyone gets anything gets done at all.

Two Steps Onward, by Graeme Simsion and Anne Buist and published by Text Publishing, is out now.