After meeting several women, I notice a familiar pattern: Every conversation, every interaction, every brush of the hair and sustained glimmer of eye contact is communicating a strong sense of desire. Sure, it's the M.O. of a regular dude on the prowl. But being in an entire room of women who feel that way? It feels alien.

A 21-year-old model named Marisol has become the ambassador of AmoLatina after winning a beauty contest in 2011. She dreams of working in London and studying engineering.

Larry, my chaperone, seeks me out. As part of AmoLatina's push for glamour and legitimization, the company hosts an annual beauty contest. Last year's competition was syndicated on Univision—the United States' largest Spanish-language TV network. The winner, a 21-year-old brunette named Marisol, is making a publicity appearance at the social. She's pretty, in a quieter way than anyone in the room. Like most of the women here, she doesn't speak a word of English. In the aftermath of her contest win, Marisol was bombarded by requests for dates. She tells me her modeling schedule was too chaotic, in the polite way most beautiful women say they're too busy. Her requirements in a man, I learn, are humble: that he is respectful and committed to being in a relationship. She implies that neither can be assumed when dealing with Colombian men.

The social is three hours old when I catch up with Jack again. Grinning, he tells me he won a prize in a dance competition. More important: He's met a girl.

"The woman I'm dancing with, Patricia, she's beautiful," Jack says. "She has her own business, she's well-groomed, she's sexy as hell, and she's reserved, which I like. But introduce me to those other girls! It'd be rude not to." We head back inside, and the two women from the start of the night cross the dance floor. They want Jack. He tells me five more minutes, but when I come back to his table, he's left. So has Patricia.

Later that night in Parque Lleras, the party district of Medellín, I meet a 22-year-old named Santiago who is a friend of one of tonight's translators. He had no idea that anything like it existed until now. "It's not normal in Colombia," he insists, aghast. "It's not normal anywhere." Another young man, loosely connected to the tour, chimes in: "I see the women who come in. They are looking for husbands, a man that can take care of anything. They are looking for a green card. There is no love in that room."

Sometimes Cupid strikes: Jack met Patricia on the tour. "She's my sweetheart," he says. "It's absolutely unique and special." Ultimately, the relationship did not last.

• • •

The phone rings early the next morning. I wake up with a jolt. It's Jack. He wants to meet by the pool and tell me about the night before. Jack lies on a sun chair and recounts what happened at the social: how he had almost overlooked the coy Patricia and kicked himself once he met her. At 32, she is 20 years younger than he is. Already enamored, Jack tells me about her job and, shyly, her breasts. He had taken her, and seven of her friends, out with a translator. "I told them to order whatever they wanted," he says. "I paid for the bill. I paid for the taxis home. I paid for everything."

He and Patricia have plans to meet again tonight, over dinner in Parque Lleras. "I don't want to be a playboy," he says. "I want to have a love of my life. So here I am." I can't shake the feeling that Jack is immensely vulnerable.

While he is out with Patricia, most of the other men are on a group date. They're partying on an open-air chiva bus—a rural vehicle repurposed as a nightclub on wheels—and climbing mountain ranges to take in the spectacular, light-sprawled valley that is Medellín. Several of the men, dates in tow, chuckle when they see the bus's four steel dancing poles. As we take off, our toothy driver flicks a button to start a high-powered smoke machine. He flicks another, shooting neon-green lasers across the bus. Dave and his AmoLatina coworker Lisa dance around the poles and each other. They dole out shots of aguardiente, but men several times their age refuse with polite grins, immune to the seduction of smoke, lights, and booze. Boston Joe sips a Coke, arms crossed. He's sitting alone, gazing blankly.