While you're sleeping, they're scattered across scorched valleys, toiling in darkness and danger to save fire-ravaged areas, and the lives connected to them, from further disaster.
There's volunteer rural firefighter Stephen Bennett, who has a very personal reason for swapping sleep for 12 hour shifts tackling hot spots, and there's John Webster, the affable overnight operations' manager from a Hira forest management company on the eastern outskirts of Nelson, who's been helping put out fires since 1981 and has a half-melted helmet at home to show for his most hairy firefighting experience.
Matt Pearless is there too. He's from the Nelson Brigade, which might seem close to the fire zone until you meet Ted Ford, a volunteer at Appleby, only a few kilometres from the Redwood Valley, the eastern-most of four valleys where residents still can't go home because of the danger.
Every day since a spark in a Pigeon Valley paddock last week flickered into a fire that swept across the equivalent of 2300 rugby fields, making it the largest in New Zealand since 1955, up to 150 firefighters have grafted across a blackened, smoky landscape in this rural enclave south of Nelson.
Every night too.
Rugby field turned field base
Night shift, all 12 hours, and sometimes more, begins with a hard left turn off Brightwater's Lord Rutherford Rd - named for the hamlet's most famous, atom-splitting son - and into Centennial Park.
The field, usually home to the blue and yellow strip of the Wanderers Rugby Club, is now a makeshift field - literally - base for the firefighting operation, including the various services around it, such as police, St John and the New Zealand Defence Force, who have put up a mess tent to feed the hundreds coming and going from the fire zone.
Every shift begins with a half hour briefing which includes a rundown of the forecast weather, an ever-present potential foe of the firefighter.
It's been a warm day - coastal Nelson Airport peaked at 25C and the day before a firefighter was hospitalised for dehydration - although lBrightwater locals reckon the temperature has topped 30C in the inland settlement.
But while Nelson's clockwork-like afternoon sea breeze has kicked up, wind hasn't been a major problem since the early days of the fire.
A mild night is expected, it's still in the low 20s and will dip only a few degrees overnight, as the night crews travel along Waimea West Rd, past the road cordon and then an eerily empty Carter Holt Harvey timber mill - saved on the second day of the fire by frantic efforts that included felling a shelter belt of eucalyptus trees on its western flank.
They're working in Yankee sector, off Eder Rd, the main haul road for the timber mill, and here the fire's impact is both head-scratching and impossible to miss.
In this Tasman Pine Forests-owned pine forest above Eves Valley, there are parts where every tree is a blackened skeleton of its former self, and there's so many of them, off both sides of the road, that failing to grasp the scale of the disaster is impossible.
But other trees look barely damaged.
"Probably the fires just sort of mosied through there and burned off a little bit of ground fuel," Webster says.
The milk tanker in the fire zone
Fires can move with frightening speed - ground crews couldn't get into this area until last Thursday because of the danger - and can also flicker along.
They can burn underground too, and dousing hot spots, that in the right conditions could flare up again, is the focus of efforts for many of the fire crews on the night shift, Webster says.
"Our brief tonight is to patrol, monitor and cool down hot spots, working away from the fire breaks."
Fire bosses are still not calling the fire controlled, but there's a roughly two dozen kilometre long containment line around it and a focus on pushing further and further in from fire breaks.
But at night, Webster, overall in charge of the operation and therefore the safety of those involved, won't be letting crews go too far from the relative safety of the fire breaks.
"Yeah, I wouldn't really want anyone down here, especially when it gets dark, more than about 20m away from appliances."
The dangers aren't just fire, further up Eder Rd 27 firefighters are preparing to work on hot spots identified by a drone's thermal imaging camera.
Nelson firefighter Matt Pearless is among them, but can't yet tackle the hot spots because of potentially unstable trees.
Leaning, looming pines tower over the tiny figures of the firefighters, and it's not unusual for trees weakened by fire to initially handicap firefighters' efforts, Webster says.
"There's an old landing and they were felling some of the trees around it but there's hot spots in there. So these guys [on Eder Rd] are supplying water, but they're in there doing a safety assessment before they put anybody in."
This is a place to always expect the unexpected.
We're in roughly the middle of the fire zone.
Pigeon Valley, where the fire began, and Teapot Valley, home to a Christian camp with an epic homemade water slide that has entertained kids for decades, are to the south; the more expansive Redwood Valley is to the north.
Any residents, and as many animals as they can gather, are gone - one home succumbed to the flames and around 500 residents from about 200 households remain evacuated - but seemingly wily and fleet-footed wild pigs and goats that call the area home remain.
There's certainly no cows, but it's no surprise to Webster to see a milk tanker pulled over on Eder Rd.
In this fire, everyone's been mucking in - from regular people buying food for evacuees, to volunteers distributing it, to any and every company that can offering to help.
The milk tanker is now a water tanker, Webster says.
"Yeah, everybody gets roped in."
'We've all got properties in the surrounding areas'
They might be roped in, but it's a fair bet they tie the rope themselves.
So many have come to help, helicopter pilots - 23 choppers were part of the fire effort at its peak - from all over the country, and staff from various support agencies, including police and the New Zealand Defence Force.
The firefighters, many volunteers, have travelled from the far north to the deep south to do their bit. And, those who've shared their stories over this longest week have been clear they wouldn't have it any other way.
That's certainly true of Stephen Bennett, a rural volunteer firefighter from nearby Appleby, part of a group of 17 firefighters working together in the darkness.
"It's real important", he says when asked why he wouldn't be anywhere but here, now, helping.
"We've all got properties in the surrounding areas, so we don't want it to get away."
There's challenges to working at night, among them simply being more vulnerable to taking a fall in the darkness.
But he also likes it, Bennett says.
"It's just something different. Different skills. And you're just out here doing something."
It's not easy speaking to firefighters battling New Zealand's largest forest fire since Sidney Holland was Prime Minister and the population was a shade over 2 million.
Without a fault they're friendly and polite, but their priority has to be getting the job done, not chatting to reporters.
Work interrupts the chance to ask Bennett what his day job is, but he does have a chance to say he's on his third nightshift in a row.
Fatigue can be an issue, especially for those who've been working nights for over a week, Webster says.
"It's starting to catch up."
He's not sure how many of the firefighters are part of the unpaid force, but is aware of some volunteers who have their own businesses.
"Some are working days in their business and nights up here, but you only do for about three days before you run out of steam."
But, there is something nice about the fire zone at night, where you work under a blanket of stars instead of the blazing hot sun.
Like Bennett, Webster likes it.
"It can be quite eerie, especially if there's a bit of smoke wafting across", he says of an area which in parts now resembles the geothermal vents of Rotorua but come spring, when the firefighters have gone and nature's work has been helped by fire-broken plants pumping nutrients into the soil, will be lush and green again.
For now, there's no noisy helicopter making continuous circuits overhead, no wind whistling through the stands of remaining pines.
It's quiet, he says.
"It's very nice. We like it quiet. Not too much wind, not too much going on. It's good for our fire."
Child's sweet message to firefighter
On the way back down Eder Rd, two firefighters have the hose on a hot spot.
The firefighters work to open up the hot spots, sometimes by hand, and then
get water in them to cool them down.
It's as simple as that.
Beyond that, it's just about priorities.
Further along, flames flicker in three or four spots, but there's no trees nearby, so they'll be dealt with later.
It's beautiful here, high above Tasman Bay where the lights of Nelson - the city for which many named a fire which really began 30 kilometres to the south - sparkle in the distance.
It'd be a good spot for a cuppa - you could put your billy over a hot spot, like Webster has seen firefighters do in the United States.
They don't need to here though, there's been so much generosity - no one needs to make their own breakfast, lunch or dinner, let alone hot brew.
Webster, a proud dad who still calls his 23-year-old daughter his "little girl", pulls a card from his pocket.
It's handmade and was tucked inside a donated lunch.
In a child's handwriting, it says 'For a true hero that saved the day (that's you!)'.
The young writer, Mckenzie Burrell, has sprinkled love hearts through her message, wee flourishes in black biro at the start of letters, and at the end of them.
"It's pretty sweet, ay," Webster says.
He opens the card to reveal Mckenzie's final message inside, smiling broadly as he reads it.