Sunday night, Les Schrenk will watch a war story on TV — about himself.

The documentary “Mortal Enemies” will tell the tale of the act of mercy that haunted him for 68 years.

Schrenk, 91, is alive today because a German pilot mysteriously spared his life during World War II. And he is at peace today because he finally found out why — after an odyssey spanning seven decades of dogged research.

Schrenk said that when he finally met the pilot, he called it a “reunion,” as if they were long-lost friends. The meeting would be full of answers for Schrenk, which he found satisfying.

“This has finally come full circle. It’s kind of the closure of everything,” said Schrenk, who will be watching the documentary in his retirement home in Bloomington.

The following account of Schrenk’s saga comes from the TV documentary, interviews, and military documents from World War II:

ILL-FATED DECOY

On Feb. 22, 1944, a squadron of bombers left England to attack Nazi factories near Germany’s Ruhr River. The mission was so important that the Allies set up a simultaneous decoy attack to distract the Germans.

In the decoy squadron was a B-17 named Pot O’ Gold. On the belly of the plane was a gun turret, and inside it waited a machine-gunner — Army Air Corps Sgt. Les Schrenk, 24, of Long Prairie, Minn.

The squadron roared over its target in German-occupied Denmark, but cloud cover prevented it from dropping any bombs. As the planes wheeled around to return home, a swarm of German aircraft attacked.

“The air was full of airplanes,” Schrenk recalled Thursday. “I swear, some of them came within a few feet of us.”

The Nazis shot three of the B-17s out of the sky, killing all 40 crew members. Then a German JU-88 swooped toward Schrenk.

“The first thing I remember was a great big explosion,” he said. He looked up at the right wing — where a 25-foot plume of flame belched from a fuel tank.

On the plane’s radio, someone asked: “Where’s the nearest land?”

The navigator replied: “Twenty minutes due east.”

This is it, thought Schrenk. Like blindfolded prisoners facing a firing squad, the crew waited for the final gunshots.

And waited. And waited.

But the German attacker had stopped firing. The crew was amazed to see it assume a protective position, floating about 100 yards over the crippled B-17.

Schrenk knew that falling into the icy North Atlantic was a death sentence, but if his plane could reach land, he and his crewmates might parachute to safety.

It didn’t seem likely. The flames went out and reignited, over and over. “It was explosion, explosion, explosion for 20 minutes,” Schrenk said.

Just as the plane crossed the beach, the wing fell off. “Ten seconds earlier and I wouldn’t be here today,” he said.

The bomber spiraled down. The crew bailed out, their chutes popping open.

As he swayed in the wind, Schrenk heard the crash of his plane three miles away. Then he heard bullets buzzing past — German ground troops had opened fire.

The 10-man crew landed without injury, with the exception of a pilot who fell into a lake and drowned.

Schrenk’s boots had hardly touched the ground when the questions hit him: What just happened? Why am I alive? Why didn’t the pilot kill us?

German troops quickly rounded up the American fliers and marched them to a nearby schoolhouse. Schrenk would soon be sent to Stalag Luft 4 — Airmen’s Prison No. 4 — in Lithuania.

DEATH MARCH

By that time, the Russian army was threatening from the east. Eventually, the camp’s guards ordered the prisoners to evacuate.

As they marched, Schrenk wondered about their destination. Days later, he realized there wasn’t one.

The guards were not taking them to another prison, but driving them back and forth across snow-covered Germany like a herd of cattle.

It was a death march that lasted three months. “If you couldn’t keep up, you were shot,” said Schrenk.

His comrades died all around him. He was constantly on the verge of freezing and starving.

He wore out the bottoms of his socks — so only rings of cloth remained around his ankles. He could see his toes wiggling out of his tattered shoes.

“I was lucky,” he said. “I was from Minnesota, and I knew about snow. Those guys from Florida had never seen a snowflake.”

At night, the men wrote poetry. Schrenk carried a notebook through the entire march — and still has it. In it, a typical poem “Discards” compares the starved men to “a broken bottle thrown away that was once a bottle of beer.”

Then, suddenly, the march was over. “One of the guards said, ‘We are your prisoners now. You are free,’ ” remembers Schrenk.

British troops had come to the POWs’ rescue, but there was no celebration.

In a hunger-induced stupor, Schrenk took hours to realize what happened. “We could hardly put one foot in front of the other,” he said.

Schrenk was one of thousands of liberated prisoners, and their sheer numbers overwhelmed the Allied forces. “Our own government didn’t come to get us,” he said.

The liberators told the ex-POWs their ordeal still wasn’t over: They had to walk 13 miles more to another camp.

The British did give Schrenk clothing — a British uniform, which turned out to be a stroke of luck. After days of trying to get U.S. forces to help, Schrenk donned the uniform and approached an American airman, who naturally assumed Schrenk was British. Schrenk finagled his way onto a transport plane and landed in England.

That’s when the war ended.

Schrenk returned to America with two Purple Hearts, moved to Edina, got married and lived in the same house for 56 years.

SEARCH BEGINS

Yet the big question never left him.

He’d look at his wife and friends, and wondered where they would be if the German pilot had not spared him.

He’d look at his daughter, who wouldn’t have been born.

The questions became an obsession, and he began his search for the only man who had the answers: the German pilot who had shot down his plane.

Despite a barrage of letters and phone calls, he made no progress. “The German government was absolutely not helpful,” Schrenk said. “Everything was classified.”

Eventually, a Danish friend, Nikolaj Bojer, came to his aid. And after four years of cutting through the red tape with his help, Schrenk finally found the name.

It was Hans-Herrmann Muller.

Schrenk found a phone number and arranged a meeting. A Danish TV crew picked up the story and began to film him. In 2012, the two men met in Muller’s alpine home in Heidelberg, Germany.

Schrenk thanked Muller and handed the German a .50-caliber bullet, which he had recovered from the site of his wrecked B-17.

“I am very glad I didn’t give it to you back then,” Schrenk told him.

Then it was Muller’s turn. He tried to say what Schrenk had waited 68 years to hear — the reason Schrenk was standing in front of him.

Muller was a battle-hardened ace who downed 16 enemy aircraft during the war. But after crippling Schrenk’s plane, he felt a sudden pang of conscience.

“It would have been foolish to shoot down aircraft over the sea. They’d have no chance of survival,” Muller said in the documentary.

Instead, he escorted the flaming B-17 to shore. “When I saw that all 10 jumped out with their parachutes, I must say — it may be too much to call it happiness — I did feel a kind of satisfaction.”

But why?

Only minutes before, Muller had mercilessly machine-gunned another B-17 into the Atlantic. Why not do the same for the Pot O’ Gold?

The only explanation — the conclusion of Schrenk’s epic saga — was a split-second decision.

But that was enough.

Schrenk felt satisfied and basked in the warmth of a new friendship.

“It was like seeing a friend from old times,” Schrenk said. “I will like him forever, and that is what he tells me, too.”

Toasting each other with champagne, the men look in the documentary as jovial as a pair of aging Rotarians. But their smiles couldn’t hide the fact that this was a curious kind of friendship.

Their last meeting was two generations earlier, in midair, as they desperately tried to kill each other.

Both knew their friendship would seem strange to others, and both felt the need to explain.

Friendship is personal, they said, but war is not.

They never thought of conducting war in terms of killing people. They never thought of their victims at all.

“If I had thought about it, I certainly wouldn’t have been able to manage 16 shootdowns,” Muller said.

“You were happy after a successful shootdown. But how many people and who would be in there?” he said. “We didn’t care about that at all, because then we wouldn’t have been able to attack more rigorously.”

Schrenk agreed. “If you shot a plane down, it was more like just: ‘Hooray! I scored a victory!’ There was no feeling, really. You are shooting at each other. You are trying to keep yourself from being killed.”

Schrenk, who lives with his wife, Bernice, in the Bloomington retirement home, said he still regularly calls Muller. The friendship continues. And the explanation of the friendship continues, too.

“People who don’t understand war ask me: ‘Why don’t you hate him?’ ” Schrenk said. “If I would hate the pilot that shot us down, would it hurt him? No. He wouldn’t know I was hating him.

“Who would it hurt the most? Me. It would make me a bitter person.”

As he folded the pages of his poetry notebook, he said, “It is much, much better to put the past the behind and move forward.”

Bob Shaw can be reached at 651-228-5433. Follow him at twitter.com/BshawPP.

ON THE AIR

“Mortal Enemies,” the story of World War II veteran Les Schrenk of Minnesota, will air at 6:30 p.m. Sunday on Twin Cities Public Television. The documentary was produced by Danish TV and brought to Minnesota with support from the Danish American Center and Danish Consulate.