It's around midnight in Ban Nale, a small village in northern Laos. Sarah Marquis is asleep in her tent by a river when she hears voices.
"I quickly turn on my headlamp and open my tent," she writes. "I find myself nose-to-nose with several men.
"I attempt to greet them kindly while they yell and blind me with bright lights. With my right hand I push aside the lamp of the man who has decided to conduct the interrogation.
"What I see sends a chill up my spine. This fellow, the size of a 12-year-old kid, has a machine gun slung over his shoulder."
Ultimately, Marquis defuses that encounter with a group of desperate drug dealers and escapes (but not before the leader discharges a round from his machine gun into the air).
At the time, Marquis was en route from Siberia to Australia's Nullarbor Plain by foot (except a passage to Brisbane via a cargo boat), in a 20,000-kilometre journey recounted in Wild By Nature.
The finishing line for the trek, which also took her through the Gobi Desert, China and Thailand, was one particular stunted, wind-blown tree in the Australian desert whose acquaintance she had made on her previous trip around the country.
It was to last three years and, far from being a terrifying one-off, the Laos incident was just one of a catalogue of shocking situations – mostly with men – any one of which could have ended in disaster.
In fact, the kindness of strangers that is so often central to the narrative of similar adventure travel books is in desperately short supply during much of Marquis' epic journey – at least until she reaches Australia.
She says simply that it is the plain, unvarnished truth of her story "as a white female".
"This is the condition of the woman in this world, alone. It is difficult," she says. "I've met some men who have been travelling in Mongolia who never had any trouble at all."
Mongolia seems to be a hell hole for the sole female traveller. For weeks on end she was harassed in the early hours by drunken Mongolian horsemen, bent on having "fun" with the unusual outsider – or worse. She was forced to behave almost as a hunted animal, making her camp deep in the woods, never staying in one place for more than a night, being careful not to leave any tracks.
Even during the day, she didn't receive much of a welcome from the people she met. Only later did she hear of a local legend almost uniquely calculated to load the dice heavily against her.
"I discovered in Mongolian culture you have this tale that has been told around the fireplace where they say death is coming when you meet a white female walking alone in a desert," she says. "After travelling in the country I heard that tale. Unfortunately in Mongolia that was probably in the back of everyone's minds who I was meeting."
Crossing solo some of the planet's most challenging regions has been a way of life for Swiss-born Marquis, since her teens, when she rode across central Turkey on horseback. Now 43, she has walked around Australia, north to south in the US and spent eight months trekking 7000 kilometres through the Andes.
In 2014, she was named one of National Geographic's Adventurers of the Year. All of which means that she bristles slightly when I call her a "traveller".
"No, no, no," she insists. "I'm not travelling, I'm exploring, which is different. I'm off the beaten track, I'm in the woods, I'm in nature, I don't follow paths. This is the big difference – I'm not travelling."
The preparation she puts into her expeditions is, as one might expect, meticulous and extraordinary in its detail. However, less expected is that, just like the Prussian general who declared "no plan survives contact with the enemy", she believes it is just as important to mentally discard all those plans from the first step.
"There is enormous preparation for the unexpected," she says. "In your mind you have to be prepared and then you have to let it go. There are two processes. One is an intellectual process and then you have to let it go and rely on your instincts. It is really complex.
"I have realised over the years that the preparation is just to make me feel good, to feel ready. But I'll never be ready because I don't know what is coming."
The obvious question is "Why?" Why put yourself through the torment, hunger, sickness and danger she described compellingly in Wild By Nature?
As with most of the people I have spoken to for whom extreme adventure is a way of life, her response manages to be both oblique and convincing.
"One word: curiosity," she says. "I am curious about everything. For me the discovery is crucial. I want to know what we are made of and the only way to know that is alone. It is with yourself and the empty places."
She also sees herself as an ambassador for the wild places and people she encounters.
"I discovered my mission. My mission is to be this little bridge between human and nature. I cross this bridge and I come back and say we need to find our sense of belonging to this planet because we all have the same address – it's here, this planet.
"If you do not take risks, if you are in your comfort zone all the time you will never achieve anything; you are just in a bath in your own juice. What I am doing is the reverse – by being outside my comfort zone I learn something about myself."
Wild By Nature
Allen & Unwin, $29.99