They rationed the water carefully: a sip in the morning, a sip in the evening. A week passed without any contact. On the 10th day, they spotted a plane.
"This was probably the most emotional exhilaration in our lives," Zamperini remembers. "We were actually three grown men; we were crying, tears running down our faces because we knew we would be rescued. Man, this was great; we'll be eating dinner with the Marines tonight."
But the pilot never saw them.
Then the shark came. "We were trying to sleep and we felt a big thud under the bottom of the raft and we just froze," Zamperini says.
"We looked out and we saw this great fin going by and it seemed to be conscious of us. Around the raft and around the raft and then it would go under the raft and thump it," he says.
"And we gave orders 'Do not move, don't say a word.' We knew that if he had any sense at all, all he had to do was just bite through the raft and he had all of us," Zamperini recalls.
After two nights of dread, the shark disappeared.
Soon the men were catching small sharks with their bare hands and eating their livers. At the same time, Zamperini was cooking up fantasies. He would spend hours entertaining the other two by going through, detail by detail, how he would prepare elaborate Italian meals.
"So I had to cook breakfast for them every morning," he says. "I had to cook lunch for them every afternoon, dinner for them every evening and pretty soon they got really selfish and they wanted brunch."
On the 27th day, they heard another plane. They took out their mirrors and sent signals to the plane, which turned toward them. Then they heard machine gun fire. It was a Japanese plane.
Russell Phillips, the plane's pilot, survived on the life raft with Zamperini.
McNamara was deteriorating. On the 33rd night, he died. Zamperini gave the eulogy. Just after dawn, he and Phillips slipped McNamara overboard.
In America, almost everyone had written them off. In Torrance, the Zamperinis kept a vigil for their son even though they had received a death certificate signed by President Roosevelt His mother was especially sure he was alive.
But the Torrance Air Field had already been named after Zamperini, and all over Southern California, newspapers mourned his death. At the Knights of Columbus track meet at Madison Square Garden, the race he had run was renamed as the Lou Zamperini Memorial Mile.
In the South Pacific, on the raft, there was no water. It had been seven days since the last rain. Then they saw clouds. It began to rain. The waves rose higher and higher. As one swell raised up the raft, Zamperini saw an island.
They made their way to it. When they washed ashore, Zamperini and Phillips were so weak they couldn't walk; they had to crawl onto the sand. They had drifted 2,000 miles all the way to the Marshall Islands. One problem: Those islands were then controlled by the Japanese.
They were welcomed ashore by Japanese soldiers, who dragged the two Americans to a prison.
"When they first put us in the cell, I just looked down at my knees, the bones and the skin and I just started crying," Zamperini says.
"Here I am an athlete. I remember myself when I was a powerful, physical athlete and now I am just skin and bones, and a, a skeleton that's all. And that brought tears to my eyes," he recalls.
Meals were delivered three times a day in the form of a rice ball thrown in the dirt. Water was almost as scarce as it had been on the raft. Nine Marines had already been beheaded on the island, and the Japanese let their new prisoners know their turn would come soon.
"They took great joy in telling us that we were going to be executed," Zamperini says. "So every morning we woke up expecting, 'Well, this is the day. This is the day they are going to kill us.'" But although they were used as guinea pigs in a doctor's experiment, they weren't executed.
On their 43rd day of captivity, Zamperini and Phillips were put on a boat heading for a Japanese POW camp. In September 1943, Zamperini and Phillips sailed into Tokyo Bay. After six months, Phillips was transferred to an officer's camp in the south.
Zamperini hoped to join him, but was instead shipped to Omori, a camp built on a man-made island in Tokyo Bay.
There, he encountered Mutsuhiro Watanabe, a sergeant. Watanabe was a brutal man, a sadist who enjoyed hurting prisoners, including Zamperini.
Watanabe spoke some English so the POWs were afraid to call him any of the things that came to mind. The nickname they chose was the Bird, because he had a big head and a strong face.
"I couldn't bear look in his eyes," Zamperini says, closing his eyes. "Even when I was punished and he'd say, 'Look in my eyes,' I couldn't do it. I just couldn't do it. To me they were that sadistic."
The Allied prisoners thought the Bird was a sadistic psychopath. His Japanese comrades thought so, too. Recently, a colleague from the camp recalled that none of the Japanese noncommissioned officers liked Watanabe, because hey thought he was too violent.
In late 1944, Japanese officers brought Zamperini into central Tokyo, to Radio Japan. And they made him an offer he felt he couldn't refuse. Knowing that Zamperini had a lot more star power than Tokyo Rose, they asked him to deliver a radio broadcast to the United States.
He wrote it in a way that his parents would know it was him. On Nov. 18, 1944, Radio Japan announced it had a special guest: Louis Zamperini of 2028 Grammercy Street, Torrance, Calif.
"Hello, Mother and Father, Brother and friends," Zamperini said in his broadcast. "This is your Louis talking. Through the courtesy of the authorities here, I am broadcasting this personal message to you. This will be the first time in two and one half years that you will have heard my voice."
The broadcast was heard in Torrance. Zamperini's family and all of Grammercy Street were stunned. A few months later officers approached Zamperini about making another broadcast, except this time Japanese hands would write the script.
Zamperini refused. His captors threatened to send him to a special punishment camp. His first thought was that he would be able to get away from the Bird.
Zamperini and eight other prisoners were put on a steam train and sent north, to Naoetsu, a cold, forbidding place on the Sea of Japan just 40 minutes outside Nagano. They were taken to a camp at the confluence of two rivers and ordered to stand at attention.
After 15 minutes, a door opened. In stepped the Bird. They were shocked. Zamperini says that was the low point of the whole ordeal.
One day in April, the Bird ordered Zamperini to look after a sickly goat. "He said, 'If the goat dies, you die,'" Zamperini recalls.
"Told everybody in the camp, 'The goat dies, he dies.' And the goat died," he says. The Bird ordered Zamp, as he was called by his buddies, to pick up a piece of heavy piece of wood and hold it above his head. Then he went to watch the fun on an adjoining roof.
"The first three minutes I could hardly take it, but then I kind of went numb, and I was just frozen in that position," he says. Zamperini, all 90 pounds of him, wouldn't give in.
Finally, driven berserk by the American's resilience, the Bird came down from the roof and punched him in the stomach. Zamperini collapsed, the four-by-four on top of him. Zamperini had been holding that plank for 37 minutes.
To find out what happened next, read "The Ordeal Ends."
Produced by David Kohn