Seconds after saying goodbye to Shake’nBake, I see my first Saguaro. Tall and green, these cacti look like cartoons, with waving arms. A western stereotype, they only grow in a small part of Arizona. Today I’ll hike to the border of Saguaro National Park through entire forests of cacti.

I’m melancholy, hiking slow in the rising heat. The new cacti are cool, but I miss my husband too much to be excited. Then, behind me on a switchback, two women appear, hiking fast. I pull over to let them pass, and they stop to chat. They’re trying to finish weeks before I will, but we’ll camp in the same spot tonight, nestled up at the park boundary. They’re the first other women thru-hikers I’ve seen, and I suddenly feel a little less alone.

The day is hot, and there’s only so far I can go without a camping permit. I siesta at a picnic shelter with a tap, chasing off the bees that live inside the faucet every time I need to refill my bottle. Down here, shade is limited to narrow bands behind saguaro, and the occasional shrub. Once the shadows lengthen, I head out, winding through waving cacti. There’s a river at the park boundary, and I set up in the sandy wash. A bikepacker camps a little ways away, and then the two women show up. Four of us watch the stars pop out, chatting about trails and the places we’ve been. My first night alone on trail, and I’m not alone at all.

I start hiking before sunrise: not a hardship now that I can barely sleep. It’s a long climb up and over Mica mountain, and I have 17 miles before I can legally camp. Normally 17 miles is nothing, but there’s over six thousand feet of elevation gain, and I’m still struggling to find my trail legs.

The sun rises, orange light filtering between the cacti and silhouetting saguaro. The trail climbs. I’m already too hot, struggling to breathe. It’s going to be a long day.

The best marker of elevation gain isn’t my navigation app, or any map. The plants let me know how high I am just as accurately. I rise out of the cacti, leaving behind the saguaro’s waving arms and the blooming hedgehog cactus. I cross the grassland, where grass seeds embed themselves in my socks. I climb through woodland, where oaks and pinion pines cast the first shade of the day. And then I’m in the pines: tall ponderosas, vanilla scented with long needles, and air that tastes of snow.

I don’t crest the summit ridge until 4pm. It’s cold up here, and I don’t pause. I start the long descent immediately. The trail is rough: ice cream scoop sized rocks roll under my ankles. My feet ache instantly. There’s a road seven miles away, where I’d hoped to see Shake’nBake, who picked up a rental car in town. But my feet scream at me until I worry about stress fractures. I can’t do it. I won’t see him tonight.

I find a perfect camp spot on a granite outcrop. There’s a sliver of service. I message Shake’nBake that I can’t make it to the road. Seconds tick past, then a message pops on my screen. I’m just around the corner, it says. See you soon.

Minutes stretch into almost an hour. There’s no sign of Shake’nBake. I’m about to pick up my pack, sore feet be damned, and go searching, when I hear heavy breathing. Shake’nBake rounds the corner, drenched in sweat. “You were only a kilometer away,” he says, after I’ve stopped clinging to him like I’m drowning. “I just didn’t realize that kilometer was straight up.” He drops his pack and pulls out gifts for me: pizza, soda, gatorade and beer. And then, shining and spotless, brand new shoes. “I thought they might help if your feet hurt that bad,” he says. There’s a lump in my throat that’s got nothing to do with the pizza I’m clutching, and everything to do with this incredible man.

I sleep well for the first time in a week. In the morning, Shake’nBake makes coffee and we pass it back and forth. It’s late when we head out, and the day is supposed to be the hottest one yet: 93 degrees. I can’t find the will to care though, not when Shake’nBake is here now. We have seven miles to the car, and we quickly make a plan. He’ll leave me there, then drive to the next road crossing, ten trail miles away. He asks me what I want. “A cheeseburger and gatorade,” I request.

Three miles from the car, Shake’nBake falls behind, pausing to rub his knee every few steps. “You should just keep going,” he says. I won’t though. I make him sit down until the pain subsides. The day is warming, and I know the delay means hiking in the heat later, but what’s more important? Making sure he’s ok trumps everything.

We make it to the car. I take a quick break in the narrow band of shade that it casts, then kiss him goodbye. The trail dips and rises through rolling hills. Everywhere is exposed: solitary trees dot the grassland, but never close to the trail. The mercury climbs until I have to pause every half hour, head swimming.

It’s ok until 4pm, when the trail climbs a few thousand feet. Shake’nBake is waiting on just the other side of the climb, no doubt wondering where I am already. I can’t keep him waiting. I climb and climb, nausea rising, until I have to pause in every shade patch. A headache throbs behind my right eye: I take a painkiller and keep going.

Just when I feel like my brain is going to bake inside my skull, I cross the ridge. I can see the road a few hundred feet below, though everything is too small to pick out Shake’nBake. I hike as fast as I can, until I half fall into the parking lot. Shake’nBake is sitting on his z-lite under a tree, and jumps up when he sees me coming.

It takes half an hour and a full bottle of gatorade before I feel better. Shake’nBake passes me two cheeseburgers, and I realize I haven’t eaten all day. The heat has chased my appetite away completely. The food helps as much as the shade. Once my heat exhaustion symptoms subside, Shake’nBake loads me in the car and we drive up Mount Lemmon to a hidden car camping spot in the pines.

I make Shake’nBake wake up early to drive me back to the trail, fearful after yesterday’s heat. Then, we linger in the parking lot for half an hour, passing coffee back and forth. Oops. Finally, I head out, three miles to another trailhead where Shake’nBake is waiting. I sit with him for a minute, eating chips, then head out. There’s no more road crossings, so I won’t see him again until tomorrow.

The trail dips down through Sabino Canyon, before rising high on the shoulder of Mount Lemmon. The elevation loss before the climb feels cruel. The trail is rough and my feet ache, until I stop for lunch beside the biggest stream on trail so far. I soak my feet while water spiders dart across the rocks.

The trail climbs steeply, up slickrock and boulders. My achilles aches from the climb. Clouds cover the sky, grey and brooding, and I’m grateful for the break from the neverending heat. Finally, I pass the boulders. The trail winds through pines, rising and falling on tiny, steep climbs. Every tendon in my ankles screams at me, until I stop and set up camp on the edge of the burn. It’s my first night alone on trail, and I wonder, am I brave enough to solo cowboy camp? I picture mountain lions standing on the boulders around my campsite, licking their furry lips. In the end, laziness wins over fear, and I lie in my sleeping bag with nothing between me and the stars.

It’s only four miles to a trailhead in the morning. I’m there before seven, but Shake’nBake is already waiting. He loads me into the car and drives me to Tucson for my first day off of the trail.