I feel like I’ve fallen into a hole in the map. This swath of Mexico is a blank nothingness of faded yellow that cuts across the states of Guanajuato, San Luis Potosi and Veracruz. No roads are indicated, no villages, nothing. Even the usual contour lines of the Sierra Madre Occidentals are missing. I’ve disappeared from the world known to cartographers.

Granted, the map isn’t very good. It’s a government freebie from the Pemex station back in Tanquian, a humble crossroads of quonset huts and mud-brick shacks that calls itself “la entrada al Mesa de Manzanares” — the gateway to Manzanares Mesa. That’s where I switched buses, arriving on a local headed back to Guanajuato, departing on another local that’s grinding eastward across mountain ridges. I don’t really know where I’m going. I just think it would be cool to experience the tropical rainforest and stroll the beachy fringe of the Gulf of Mexico. Better do it before my tummy swells into awkwardness. And before my money runs out.

I’m despairingly familiar with converted schoolbuses, the cheapest transportation in this part of Mexico. They’re obsolete rusting castoffs from school districts in America, identifiable by the graffiti carved into their fiberglass side panels — “Class of 87″ and “Joe + Kristi” and “Iron Maiden Rulz”. Their Mexican owners bolt luggage racks onto their roofs and repaint them in vibrant rainbow colors and give them weird names, like Triste y Abandonado — Sad and Abandoned — and El Pollo Loco — The Crazy Chicken. Torn vinyl seats are reupholstered with duct tape, and any busted springs protruding are just ripped out. Then they’re put into service on these single-lane dirt roads, bouncing violently and making a horrible racket and spewing a dirty black fog of diesel smoke.

Outside the bus windows a ruggedly beautiful world is lurching into view. The flat earth-toned scrub of the Manzanares Mesa is gone, replaced by a hilly riot of greenery — bottle palms, the woody vines known as ojite, cedars spreading their canopies in the muggy air. We stop in picturesque Indian villages. Men loiter in campesino outfits of straw hats, white long-sleeved shirts and pants with huarache sandals. Elderly women in traditional hand-embroidered huipiles sweep the dirt streets, while chickens and dogs wander past their ankles. Conversations are filled with a mixture of Spanish and a language I’ve never heard before, probably Nahautl, the mother tongue of the Nahua Indians.

I’m still angry about my unplanned stay in Ahorcado, where the stupid bus driver left me behind during a break. So I don’t get off the bus when we stop. Instead I just gaze out the window, carefully draping my bangs over the right side of my face. But my crooked wandering eye comes in handy when an inebriated Indian climbs aboard and crowds into my seat, all groping hands. A toss of my hair to reveal the Evil Eye and he stumbles away in horror.

Thunderheads are boiling into a sky that’s the color of Nick’s icy blue eyes. Lines of palm-covered hills rise out of a pooling fog. The humidity becomes cloying, then almost unbearable. There’s so much water vapor in the air it feels as if I could drown. I pray for rain — for relief — but there isn’t any, just an elongation of sweat and panting. The bus grinds on.

Then all the world seems to thicken and blur. Fog is swirling into the darkening sky, whipped by a sudden cool wind. Thunder rumbles closer. A jagged bolt of lightening arcs overhead, followed by an ear-splitting craaaaaaackle-BOOM!!! Small children on the bus erupt in wails, and their tears seem to provoke the sky. A few raindrops dot the windshield, then more, then a lashing torrent.

Passengers struggle at the twin lines of windows, trying to work mechanisms that are old and rusty and clogged with dust. Only a couple windows actually close. The rest remain stubbornly open, letting in sheets of rain that pour down the roof. My window refuses to budge and within minutes I’m drenched, a soggy backpack in my lap.

A drowned-looking rooster escapes its owner and begins jumping from seatback to seatback, squawking and flapping and pecking. When it lands in front of me I raise my backpack defensively, terrified the crazy bird will peck my eyes out. Suddenly the bus lurches and we’re both thrown violently against the side. I bang my temple hard and elbow harder. The rooster disappears out the window in a blizzard of wet feathers.

Around us the torrential downpour is turning the single-lane dirt road into a river of mud. The steady straight-ahead grinding of the bus becomes increasingly erratic, punctuated by fishtailing and enormous pothole splashes. Sometimes the bus driver curses louder than the thundercracks. The wind is blowing so hard that branches are reaching through the open windows and trees are caving away. I notice the Indian woman sitting across from me is bracing herself with one hand and fingering her rosary with the other. Something in her calmness makes me panic. Suddenly my life — my dumb pointless life — is flashing before my eyes, a slideshow of memories that I won’t miss…until I get to Nick, and omigod, I don’t want it to end this way, buried in a mudslide or crushed underneath fallen trees, not when I’m pregnant with his child, not when I’m so in love with him.