I'm slumped on the side of the road, surrounded by rolling vineyards.
My bike lies beside me, as incapable of motion as my own red, sweaty limbs. Wavy lines wobble skyward from the piping hot tarmac, and I strongly believe I might be dying.
"Hey honey! You need a ride?"
A white SUV appears as though a mirage, its concerned owner peeking over designer sunglasses at me, her hair falling in perfect glossy waves (mine is clamped to my forehead under my clammy helmet).
"I'm fine! Just taking in the scenery!"
It takes every ounce of energy I possess to wave her on, as I realise that my only option is to get off my backside, and put it straight back on the saddle.
This is all my own fault. A combination of deadlines and a painful foot injury meant that I haven't trained for this rather epic cycle around Northern California's wine country. But here I am, on a brand new cycling holiday organised by Grand American Adventures, a small group adventure specialist for 35- to 65-year-olds. My trip weaves through Napa Valley and Sonoma County, led by Mike May and Tavis Moses.
I met them in San Francisco, and as we made our way to the starting point in Napa, I decided that I liked them both instantly. Tour guides in previous lives, they've known each other for donkey's years, and as a team they offer everything you could ask for - they're witty, laidback, and they don't laugh at me when I struggle up a hill.
And struggle I do.
As any cyclist will tell you, the first ride after a long break is always a killer. So when I finally reach Mike and Tavis, who wait for me a little up the road, Mike gently suggests that I ride in the support van for the next few miles.
Surprisingly, I don't feel any guilt, just pure, unbridled joy as we scale the monstrous hills on four wheels rather than two. When I hop back on the bike and reach El Pueblo Inn, our hotel in Sonoma, a jaunty little song plays from the GPS strapped to my handlebars. I've never been as happy to see a finish line.
And let me tell you, my evening glass of wine tastes pretty damn good, as we sit in the terrace of HopMonk bar, the Sonoma Plaza glowing like Jurassic Park amber in the early evening sun. But while the vineyard-hoppers around us are free to enjoy their wine with wild abandon, we're on a different schedule.
Each morning begins with a logistical plan over maps at breakfast. I eat as though I'm being sent off to battle, and ask endless questions about the day ahead. Mike sorts the bikes before we head off, pumping tyres, checking the day's route on our GPS devices and gallantly ignoring the yelp I make every time my bum hits the saddle.
And while the distances look intimidating, I know that I could always hop into the van if ever it gets too tough.
The thing is, I never want to. Sure, there are times when I want to stuff a spare jumper into my shorts (saddle soreness is no joke), or when I pull over halfway up a hill just to take a break, as elderly Californians sail past me and I curse darkly under my breath. But when I pull into the stopping points, fill my water bottle and slurp a disgusting pouch of energy gel, I never actually want to quit.
We fall into an easy pattern, Tavis cycling ahead and drifting in and out of eyeline, as we make pit stops for flat whites in the pretty town of Petaluma, or protein bars at the roadside, where Mike hands out treats and encouragement.
We weave our way to the coast, the first glimmer of ocean appearing over the wide, flat rocks outside Tomales. The trees grow taller, and the air cooler, making the sizeable hills all the more manageable.
The late afternoon sky thickens with fog as we cruise into Bodega Bay, which is oddly fitting, considering this was where Alfred Hitchcock's The Birds was filmed.
Our hotel, Inn at the Tides, looks out over this murky, moody water, and as a foghorn blasts I decide the best place from which to drink in the atmosphere is from the hot tub, an ice-cold beer in hand (pictured below). The piping hot water feels inexplicably good, and the condensation drips saucily down my can of beer as I brag to the holidaymakers who join us ("Oh us? We cycled here from Sonoma, 80km, no big deal.")
Though the next morning is damp with mist, we hit the road early, my bum clenching (as well as it can) as I speed down a few of the undulating hills that line the coast. We're finally on the Pacific Coast Highway, and the scenery is the kind that makes you feel positively giddy, and grateful that we live on such a pretty little planet.
Tiny pink daisies grow up from the rocky cliff edge, violent waves crash against the shore below, and California poppies spurt up on the roadside as I sail on past. Sauntering up the coast I start to feel strong, and exhilarated. It would be one thing to drive up this infamous road, but seeing it from a bike is something else altogether.
And just when I think it can't get any better, we hit the redwoods. As we move in from the coast the road cuts through the mountains, the fog clears and these towering trees appear, piercing the blue sky and soaring towards the heavens. Mike has driven on ahead, and when we stop at the Armstrong Redwoods State Natural Reserve, he's waiting in a clearing, next to a picnic table filled with platters of turkey wraps, fruit and energy bars. It tastes incredible, all smothered in that rich sauce of smug adrenaline and endorphins.
When we leave the redwoods, the sun is splitting the stones, the roads soundless bar the swoosh of my tyres. The vineyards return, the bird-repelling silver ribbons adorning the vines shimmering in the sunshine. I stop at the roadside to snap a picture and steal a tiny grape from one of the vines, the small and dusty globe bursting with juice.
It has been, without a shadow of a doubt, the best day I've ever spent on a bike.
And I only get stronger.
Towards the end of my week, I'm even keeping up with the machine that is Tavis, cycling alongside him, nipping into cute general stores for kombucha and chatting as we soar along the empty roads. I manage to indulge in my number one hobby (asking nosy questions about other people's lives) whilst simultaneously partaking in the second favourite (cycling interspersed with eating).
And let me tell you, California is a dream to cycle through - the motorists are respectful, and the cycle lanes gloriously wide.
As we drift back towards the direction of Napa, the sun heats up a few degrees, the horizon seems to broaden and the landscape becomes beguiling in a different way - the arching trees dripping in Spanish moss and dappling the roads like tortoiseshell.
It's all head-spinningly gorgeous, and as we approach Napa once again, I can't believe it's all over.
This is the finish line I've been waiting for all week, but if I could turn my bike around and start all over again, I would.
And this time, I'd get up that blasted hill.
Where to drink
For wine tasting, I loved Twomey Cellars (twomey.com), Preston Farm (prestonfarmandwinery.com) and VML Winery (vmlwine.com). For beer, HopMonk (hopmonk.com) in Sonoma is great.
Where to eat
I still dream of the BLT I had in the Healdsburg Bar and Grill (healdsburgbarandgrill.com), and El Farolito (elfarolito2000.com) is an excellent Mexican spot, with great fish tacos and devilish Margaritas.
Going the distance
Over six days, I cycled a smidge over 300km, climbing a total of 9,111 feet. Each day, there's a main route and a more strenuous 'burner' option, for those who want to really push themselves.
Nicola was a guest of small group adventure specialist, Grand American Adventures (grandamericanadventures.com). The six-day Cycling California Wine Country tour costs from €1,819pp, including accommodation, a custom fitted bike, breakfast and some meals.
Fly to San Francisco direct with Aer Lingus (aerlingus.com) from €480 return.
Calistoga Motor Lodge & Spa (calistogamotorlodgeandspa.com) is a deliciously retro motel with an incredible hot spring spa (and a massage is included in the trip); rooms from $209 (€186). Inn at the Tides (innatthetides.com) has great views in Bodega Bay from $239 (€213).
Obviously, you'll need all your regular cycling gear, and it's a good idea to bring at least two of everything - padded shorts/tights, short- and long-sleeve jerseys, then gloves, helmet, etc. You'll be cycling on chilly, foggy mornings as well as sweltering afternoons, so layers are key.