The younger tour members, though, are in their element: Going drink-for-drink with the guides, grinding on their dates, and belting out barely remembered song lyrics with comical conviction.

A little after midnight, the text comes in: PARTY IS IN ROOM 1410...

The bus party is over and the half-dozen couples are back at our hotel. Translator Laura and I snatch a bottle of Chilean wine from the corner store—we'll need an offering for entry. The door swings open. It's the aftermath of a boozy soiree in Aggie's suite, and his last two guests are stumbling out as we stumble in. All that's left of the party is Aggie, his date, a half-dozen bottles of Grey Goose, and a tiny bedside radio blaring reggaeton. Sensing that we are intruding, Laura turns to leave the room, but Aggie insists we stay. He pours us some vodka and explains that rain foiled his plans for a pool party. Then he starts talking L.A. Clippers basketball, reminiscing about Blake Griffin's nasty, iconic dunk on Kendrick Perkins of the Oklahoma City Thunder. His date, Tiana, remains expressionless but unwaveringly pleasant. Her body may be in the same room as we are, but she's absent in every other way. It's after 2 a.m. when Laura and I leave, and Tiana is still sunk into the couch.

On the bus: The partying continues the day after the disco. Note the dancing poles, mirrors, and colorful lights in the background.

I see Howard from the plane the next night and describe the scenario. "Some girls have no hope," he says. "They start thinking, 'I'm sitting here and doing nothing, or I'm sitting at home doing nothing.' The life has been squeezed out of them."

• • •

On our final day, Colombia reveals her sultry charm. I forget about Pablo Escobar and nose candy and the kidnappings I've read about and start to see a city of immense cultural wealth and enchanting, hospitable people. Plus, the country is a gastronomical joy: A punchy seafood ceviche elicits daydreams weeks after I return home. Today the sun is high, the air is crisp, and markets flow through Medellín's veins.

Larry, Jack, and I sightsee. We search—fruitlessly—for a place to play tejo, a fading national sport that combines lawn bowling with explosives. We take in Medellín from a mighty height, riding to its highest point in a panoramic cable car. As we sit, suspended a hundreds feet above the city, Jack is more certain about Patricia than ever. "She's my sweetheart," he tells us. "It's absolutely unique and special. It's the way she makes me feel, it's the way I make her feel."

For a younger man, such hasty proclamations would be warning signs—a young adult straining for significance. But this is Jack, and it's hard to qualify. Whether it's Jack's affirmations or Aggie's vodka-soaked fantasy, the tour has stirred something in each of the men—fleeting vignettes of what they want most in life. "I'm anticipating tonight more than anything," Jack says. He's planning to spend every minute of his last evening with Patricia in the hotel.

A few hours later, before Patricia arrives, I introduce Howard and Jack over some rum in the deserted hotel bar. Despite spending the better part of 12 hours with me today, Jack only now reveals that Patricia has two children. He's looking over to the lobby, distracted. "I don't want her to show up early and me not be there for her," he says. "Wait, is that her? I have to go check." And with that, he leaves, his bright eyes charmless for the first time.

"He's running out there to go find this girl, and I'm sure he's in love," Howard says. "But he's committed his heart so early. She's got a couple of kids." Would the father stoop to exploit the situation by using the kids as a way to get money? Howard has seen worse.

When we depart Medellín at 7 a.m., the sun yawns through the plane's windows and reality regains its hold. The night before, I saw Boston Joe and Aggie—drunk on aguardiente—wandering around party central in Parque Lleras looking for a bar called Sunrise. They asked the locals, but it was 12:15 on a Wednesday morning and they were out of time and out of girls. For all the promise of life-changing love—even marriage—the men depart exhausted, hungover, and a little more than $2,000 poorer.