One night in Khartoum, Sudan, Osama bin Laden decides to take his family — four wives, 14 children — on a camping trip.

He drives into the desert, finds an isolated spot, then has his oldest sons dig ditches in the sand, long enough to fit each person. It’s the early 1990s, and bin Laden believes there’s a war coming between Muslims and the Western infidels. This is training.

“You must be gallant. Do not think about foxes or snakes,” he says. “Challenging trials are coming to us.”

Each child, including a few 1- and 2-year-olds, lies in a hollow. There is no water or food.

As night falls, a child’s voice whispers in the darkness, “I’m cold.”

“Cover yourself with dirt or grass,” bin Laden snaps. “You will be warm under what nature provides.”

Bin Laden’s first wife, Najwa, doesn’t like that idea, but, “I reminded myself that my husband knew much more about the big world than any of us. We were all pearls to my husband, and he wanted to protect us.”

That’s what it was like “Growing Up bin Laden,” the title of a forthcoming memoir (St. Martin’s Press) co-written by Najwa, who remains married to the monster, though she now lives apart from him in an undisclosed Middle Eastern location, with her fourth son — of 11 children — Omar.

It’s a world where women are never allowed outside the house, 12-year-old daughters are married off to 30-year-old al Qaeda fighters, pet dogs are used for target practice and the biggest household fight is over whether Islam allows refrigerators. “Jon & Kate Plus 8” it ain’t.

It is not the life that Najwa, now 51, would necessarily have chosen for herself, though she accepts it because “my husband says it is so.”

She neither defends nor lashes out at Osama. Terrorism is what he does for a living; all she needed to worry about was keeping his house in order.

Despite her neutrality, her story is still an indictment — showing us a terrorist leader who is embarrassed easily, obsessed with a long-dead father, terrified of women, and who thinks of his children as nothing more than cannon fodder.

Najwa grew up a rebel in the port city of Latakia in Syria. She refused to hide her hair and wore colorful dresses that didn’t cover her face or arms. She attended school, played tennis and was a fledgling artist who painted portraits and landscapes.

She met her first cousin Osama, the 9-year-old son of her father’s sister, when she was just 7.

“He was such a serious, conscientious boy,” she writes. “He was proud, but not arrogant. He was delicate, but not weak. He was grave, but not severe.”

He was also “shyer than a virgin under the veil.”

Osama was the son of Mohammed bin Laden, a construction kingpin and one of the wealthiest men in Saudi Arabia. He had the habit of calling his sons for inspection, then whipping them with a cane if they did not line up exactly by height.

Though conservative in most other ways, Mohammed delighted in having his wives re move their veils, then asking his nervous servants to pick the most beautiful one. Osama’s mother, tired of these shenanigans, divorced him.

Osama had a one-on-one conversation with his father only once. At age 9, he decided he would like a car. Escorted by his stepfather, he petitioned Mohammed.

“I will not give you a car. I will give you a bicycle,” the father replied. Osama went home crushed and gave the bike to a younger brother.

Then, as Osama recounted to his son Omar years later in the Tora Bora mountains of Afghanistan, “one day several weeks later I received the biggest shock of my life. A shiny new car was delivered. For me! That was the happiest day of my young life.”

Soon after, Mohammed was killed in a plane crash, an event Omar believes left deep scars.

“Although my father was never one to complain, it is believed that he keenly felt her lack of status, genuinely suffering from his father’s lack of personal care and love.”

Osama concentrated on reli gious schooling, becoming more conservative by the year. His way of flirting was by saving the best grapes from Najwa’s back yard for her.

Their wedding in 1974 — she was 15, he was 17 — was a telling precursor to a joyless marriage. Dancing, joking and laughing were forbidden at the nuptials.

They immediately departed for Jeddah, Saudi Arabia, where she was forced to wear the “dreaded veil” and full-length black robes. Her schooling was discontinued, tennis lessons canceled, her artwork forgotten. Najwa was almost perpetually pregnant, as Osama said it was important to make many warriors for Islam.

She lived a life in purdah, where females socialize only with members of their family. In nearly 30 years of marriage, she left the confines of her home only to visit relatives and to move to a different house.

Air conditioning, televisions, phones were all banned. Toys given as gifts to the children were destroyed.

Omar’s asthma was treated with honeycombs and onions, since modern medicine wasn’t allowed. Everything the family ate had to be bought the same day, since refrigerators were out of the question.

Bin Laden took three more wives — one picked by Najwa, though she admits that “few women dance with joy when they contemplate sharing their husband with other women.”

In 1979, the couple visited America. Bin Laden went to see Abdullah Azzam, a teacher and mentor of bin Laden who preached about jihad in Los Angeles, while Najwa stayed in Indianapolis with a family friend.

She recalls how a man stared at her black Saudi robes, veil and head scarf as they waited for a return flight to Saudi Arabia at the airport.

“With a jaw dropped open in surprise, and curious eyes growing as large as big bugs popping out of his skull, he actually stopped to gape at my veiled face,” she says.

“I wondered what my husband was thinking. I took a side glance at Osama and saw that he was intently studying the curious man.”

Najwa says Americans were kind and friendly, but the country was not to her conservative tastes. “My husband and I did not hate America, yet we did not love it,” she writes.

Bin Laden became a hero in Saudi Arabia because he fought the Russians in Afghanistan. But he began to clash with the royal family after they ignored his offers of military aid and instead let Americans liberate Kuwait in 1991.

The final straw, Omar writes, was when his father saw female American troops on his soil.

“Women! Defending Saudi men!” he cried.

Under pressure from the king, Osama went into a self-imposed exile in the Sudan.

Najwa and Omar describe two Osamas here. One happily tends his garden, delighting in sunflowers. The other walks with a Kalashnikov and a cane, wielded if any of his sons showed their eye teeth while smiling.

One is so embarrassed when his boat goes out of control that he slips into the water so no one can see him. The other rants into a Dictaphone, spouting epithets about America and Israel, pausing only to listen to his favorite station — the BBC — on a small radio.

One is a legend who has radicals visiting “to breathe the same air.” The other is a wounded man, secretly blinded in his right eye by a flying chunk of metal in his youth, who trained himself to use his left hand rather than being seen as weak by a culture that rejected the disabled, Omar says.

Pets met horrible ends. A monkey the children loved was run over by one of Osama’s men. Bin Laden had told him that “the monkey was not a monkey at all, but was a Jewish person turned into a monkey by the hand of God.”

A litter of puppies the boys adopted was gassed by al Qaeda fighters to see how long it would take them to die.

Finally, under pressure from the royal family and after assassination attempts, Sudan kicked Osama out.

In 1996, he found shelter with the Taliban and set up camp in earthen huts in the mountains of Tora Bora. Najwa’s kitchen consisted only of a portable gas burner to make food for 10 kids. The children slept on cotton mattresses on the concrete floor, and there was no furniture.

Bin Laden drafted his sons to be suicide bombers.

“Listen, my sons, there is a paper on the wall of the mosque. This paper is for men who are good Muslims, men who volunteer to be suicide bombers,” Omar recalls him saying repeatedly. One of Osama’s youngest sons ran to the mosque to sign up; his father did nothing to stop him.

When Omar responded with anger, bin Laden told him, “You hold no more a place in my heart than any other man or boy in the entire country.”

Omar once approached his father about his jihad obsession.

“My father, when is this killing and war going to stop?” he asked his father.

Bin Laden responded, “Would you ask a Muslim when he was going to stop praying to God? I will fight until my dying day! I will fight until I breathe my last breath! I will never stop my fight for justice! I will never stop this jihad!”

As for why bin Laden focused on America, he said: “Remember this: America and Israel are one bicycle with two wheels. The wooden wheel represents the United States. The steel wheel represents Israel. Omar, Israel is the stronger power of the two. Does a general attack the strongest line in battle? No, he concentrates on the weakest part of the line.”

A 20-year-old Omar eventually fled Afghanistan and begged his mother to do the same. Najwa decided to leave; her husband reluctantly conceded.

In the first week of September, Najwa handed Osama a ring as a token of her love.

“No matter what you might be told, I will never divorce you,” he said.

As she stepped foot in Syria a few days later with three of her children, the world changed. She watched the television in horror as the Twin Towers fell, claiming the lives of 2,991 people.

Though she refuses to criticize — or even implicate — her husband, she says: “I can only think and feel with my mother’s heart. For every child lost, a mother’s heart harbors the deepest pain. None can see our sons grow to men. None can see our daughters become mothers.”

Najwa says she has not spoken to Osama since the attacks and does not know where he is.

Omar, who has completely rejected his father and is petitioning to live in England, was at his uncle’s house in Saudi Arabia when he learned of the attacks.

“Come quickly!” his uncle said. “Come and see what my brother has done! See what your father has done! He has ruined our lives! He has destroyed us!”

scahalan@nypost.com

