It all started two years ago in a Dunkin Donuts parking lot in Allentown, Pa., when one 20-year-old and three 19-year-olds (two of them Yalies) decided to open a bar in an old Western Union in New York City. It all likely ended over winter break this year, when What Bar — now a hugely popular Columbia watering hole and well-regarded neighborhood haunt — sold for an offer, they say, so good they couldn’t refuse.

Their story is a Yale fairy tale, the kind that makes high school seniors drool, about the Ivy League Midas touch. Four underage college students, whose collective bar visits could have been counted on a single pair of their hands.

They had no business experience, no bartending experience and no managing experience, and still they opened their doors one day, became “The Place To Be” the very next, and sold less than a year later for considerable profit.

They learned, in the end, according to Joshua Kriegman ’03, one of the four partners: “You can pretty much do anything you want as long as you pretend you know how to do it.”

But Kriegman and the other Yale partner, Daniel Squadron ’03, insist that it was neither a venture for profit nor the Cinderella story it seems. At every stage of the bar’s creation, they say, there were obstacles that could easily have collapsed the whole project. They didn’t know how to raise money. They didn’t know how to mix drinks. There were no guarantees about getting a liquor license or turning profits to repay loans.

And beyond that, there was the dismal opening night when their first investor, a heart surgeon, backed out and the long hours of work and countless nights spent sleeping on top of a chest freezer in the back room.

“A lot of people learn as they go,” said Squadron. “We learned after we went.”

Along with two of Squadron’s friends from high school, Dan and Raul, the four secured the location for Bar 109 Corporation at 109th Street and Amsterdam Avenue, just on the periphery of Columbia University’s campus, the summer after their freshman year, they said. On Nov. 3, 2000, all four, still underage, applied for a liquor license. While the city evaluated their application, Squadron turned 21, finally legally old enough to hold such a license. And old enough to start going to bars.

They began to plan the interior of the bar, deciding they wanted a full kitchen with good food, as many distinct sections of the room as possible, and a comfortable and not pretentious atmosphere, they said. Each would take a year off from school — with the blessing of his parents — to build the business before it opened.

Staggering the leave by one semester, Kriegman and Raul started work during what would have been the first semester of their junior years, and Squadron and Dan joined them one semester later.

They opened in a hurry on March 7, 2001, they said, eager to catch students before they left for the summer, to start paying back high interest loans.

The first night was a dud.

The second, they sat almost alone on the edge of the sloping wooden bar until 11:00, when “the whole Columbia campus showed up.”

“Eventually,” Squadron said, “we had to start turning people away because we didn’t know the fire codes. We had 150 people in there, and one door that opened in.”

The four had paid someone to teach them how to bartend, rather than hire a professional, and all ended up behind the bar, with no idea what goes in a “Sex on the Beach” and forgetting to give people limes and salt with their tequila shots. They were the bouncers and the managers too.

And, on the way home the next morning, after hours of cleaning up, Squadron said he laughed from the George Washington Bridge to his apartment in the Bronx: a donut shop musing suddenly realized.

Soon after, the line went around the block three or four nights a week, they developed a neighborhood Cheers-type crowd for weeknights and afternoons and a good reputation in the community. There was the “What Burger,” which they say was phenomenal, and the “What Dream” — a cheeseburger, french fries and beer for $6 — which they call the best deal in New York, hands down. Eventually, they hired a bouncer, then a bartender, and then a manager to report to them, they said.

And, predictably, they have plenty of stories. They bought everyone in the bar a round, they said, when each owner besides Squadron turned 21 — in April, June and August 2001 — and uncorked 21 bottles of champagne for their last hurrah on New Year’s Eve. They received the offer at the end of the year, after a “fun nine months,” though the ink is not officially on paper yet, they said.

“We promised our parents we’d finish college,” Kriegman said, “and it’s really difficult to run the business on the side while being in school.”

And in the end, they said, it was not just four college kids with a successful pet project.

As Squadron said, “It wasn’t all sucking on taps. There are real people whose real lives were involved in this.”

Those real people, he said, will likely lose their jobs when the sale is finalized. Moreover, some of the regulars cried, Kriegman said, after hearing they were selling.

But they look back fondly, on the year, a short story with a happy ending.

“The romantic ideal of the bar really does exist,” said Kriegman, “and we really did experience it.”