CHARLOTTESVILLE, Va. — A champagne bottle-shaped balloon broke free from thousands of bobbing balloons held by University of Virginia graduates Saturday morning and drifted off into the blue sky over the school’s historic Rotunda, with the black-robed crowd cheering it on. Just before the graduates marched up the stairs to walk the Lawn for commencement weekend, Sanjana Sekhar, holding her own balloon, handing out stickers, smiled and said, “I think this is what Otto would want — for us to enjoy the day, and think about him too.”

Amid all the joy, and the orange sundresses, and the cartoon-like balloons, and the promise of bright futures, and the beaming parents snapping photos, one person was missing.

Otto Warmbier, whose classmates at U-Va. are graduating this weekend, has been detained in North Korea with no contact with the outside world for well over a year.

His parents, Fred and Cindy Warmbier, didn’t come to Charlottesville from their home in Cincinnati this weekend. “It felt to us like a wake,” Fred Warmbier said. They wanted everyone else to enjoy the day.

“There’s not a day goes by that I don’t think about Otto,” said U-Va.’s president Teresa Sullivan, and how to help in a confounding situation.

In the mass of graduates Saturday morning, people kept reaching out to his friends, who were handing out piles of stickers that showed a padlock swinging open and the message: #FreeOtto (and a border repeating “We miss you” over and over) for graduates to wear on their caps and gowns. It was an effort to keep the 22-year-old  – described by friends as quirky, funny, charismatic and studious –  in everyone’s thoughts.

Warmbier always seemed to have everything planned out, friends and family said, from his intended career path to his workout sessions. Until January 2016. Now his future is completely unknown.

He went to North Korea with a tour group in January on his way to a U-Va. McIntire School of Commerce study-abroad program and was not allowed to leave the country.

“There’s no reason to have him detained,” said Sen. Rob Portman (R-Ohio), who has met with more than two dozen officials from the U.S. and other governments, as well as other experts, to try to find a resolution. Warmbier apparently tried to remove a propaganda poster as a tourist memento — a move that prompted considerable criticism from those who felt he should have avoided the country entirely and that resulted in a charge of “hostile acts against the state” and a 15-year sentence in prison with hard labor.

A State Department official said in a written statement the sentence is unduly harsh for the alleged offense. “Despite official claims that U.S. citizens arrested in the DPRK are not used for political purposes, it is increasingly clear from its very public treatment of these cases that the DPRK does just that.

“Mr. Warmbier has gone through the criminal process and has been detained for more than a year.  We continue to urge the DPRK to pardon him and grant him special amnesty and immediate release on humanitarian grounds.”

Or as Portman said, “He’s a college kid. He shouldn’t be used as a pawn in a broader geopolitical dispute between our countries.”

As tensions between the two nations escalate — nuclear tests, missile launches, threats and warships — Otto Warmbier’s friends are increasingly worried.

“It’s a national security issue,”  Sekhar said. “And — he’s our Otto.”

Their Otto was a top student at U-Va. with a prestigious academic scholarship intended for the most intellectually curious. He’s a sports fan who can reel off stats about seemingly any team, a friendly Midwesterner who can break down underground rap lyrics (and craft some of his own), a deep thinker who would challenge himself and others to question their place in the world, a guy from an entrepreneurial family who ate half-price sushi, an insatiably curious person with a strong work ethic and a delight in the ridiculous.

He might bang on a piano (without knowing any keys), swing a girl onto his back for a piggyback ride home, wear an immaculate tuxedo or show up for a formal event in a $2 royal-blue blazer from Goodwill.

He’s a loyal friend. And he was a planner.

His calendar was full of hand-written commitments, from courses he would take (mapped out from the earliest days of college) to academic assignments, to social plans, such as bringing a friend with disabilities to basketball games.

“If Otto had anything schoolwork-related, job-related, family-related that he needed to do,” his friend Ned Ende said, “there was absolutely nothing you could say to him to convince him to do stuff with you.”

With a sharp interest in economics, Warmbier knew early on — when most of his friends had no idea what to major in — that he wanted to go into investment banking, and he had already completed some advanced training in financial analysis in his sophomore year.

By the fall of his junior year, he had a summer internship locked in. He wanted to travel, study abroad and visit places such as Israel, the Galapagos and Cuba while he could, places entirely different from his hometown; he knew 80-hour work-weeks were ahead, and then graduate school.

Ende said when he thinks of his friend he remembers him in fall 2015, in the chair at his desk wearing, with confidence, a thrift-store cardigan covered with lighthouses, hanging up the phone and saying, “I got the job.”

“There are not too many people around the country saying those words” about the sought-after internship, Ende said. “And there’s no one in the country who would be saying those words while wearing a lighthouse sweater.”

When Otto Warmbier didn’t arrive in China in January 2016, according to plans, his friends and family worried. But many assumed it was a mix-up. One of his roommates, Emmett Saulnier, said they were sure he would be able to return soon. Days passed. Classes resumed for the spring semester.

Warmbier’s family and friends kept quiet, counseled by the State Department to be cautious. In early March of 2016, Fred and Cindy Warmbier got one message from their son, relayed through a Swedish official. Later that month, North Korea released video of the trial.

That was the moment when they realized the gravity of the situation, his friend Tim McKinney said. They would hang out in his room at their house, full of his things but empty, missing him. They tried to fathom a 15-year prison sentence — almost a lifetime for college juniors.

For Saulnier, it was a relief to see images of his friend alive. The off-white blazer Warmbier wore in the video made him smile, too; it reminded him of his friend’s thrift-store turtlenecks, Hawaiian shirts and throwback jerseys.

But time kept passing. Senior year began. The election came, a new administration. No news.

“We’ve been talking about this a lot over the last year for sure,” his friend Zach Gelfand said. “Graduation day has been creeping up on the calendar, and we have been thinking a lot there is someone who should be with us, but he’s not. That’s breaking our hearts.”

“I’ll carry that with me as I walk the Lawn,” said Tim McKinney.

Warmbier would have been wearing something odd under his robes at Sunday’s ceremony for McIntire graduates, something from a thrift store, Ende said. He would have been smiling a huge, confident smile, McKinney said. Proud of his hard work and excited for his future, Gelfand said.

“He’d probably come up with some ridiculous plan for us one of these nights to go do,” Saulnier said.

Sekhar feels certain Warmbier is thinking of commencement, these days, wherever he is, whatever he’s doing.

People kept reaching for the stickers Saturday morning, under the masses of silly balloons  — horses, flamingos, pizzas, diplomas, unicorns, basketballs, duckies — glinting in the sunlight . “It speaks to the network of people he’s been able to touch,” said Dan Matson, a friend from Virginia. “That’s why it’s spreading so infectiously.”

“We miss him, we love him,” Saulnier said. “And we know that he’ll be back soon.”