SINJAR, Iraq — Khodeda Abbas is one of the saved. His wife went into labor coming off the mountain and needed medical assistance right away. The couple had just arrived at a shabby medical tent 20 kilometers from Mount Sinjar, along with hundreds of other refugees rescued in tractors, buses and cattle trucks. The drivers were all volunteers, men with enough gasoline and empathy to cross the desert and take exhausted strangers from Iraq into Syria over a border made only of dust. The tent had run out of medical supplies three days earlier.

It was here that Abbas smoked the best cigarette of his life, he said, after becoming a father to the sleeping baby in the milk crate by his feet. He named the child Farman. “It means ‘the tragedy,’” he said, “to remind him of where he came from.”

The tragedy in question began nine nights earlier, on Aug. 3. News of it arrived through the screams of the neighbor banging on Abbas’s door in the village of Siba Sheikh Khidr, on the outskirts of Sinjar town in northwestern Iraq: “Peshmerga have left. Daash are coming.” (Peshmerga are Kurdish security forces; Daash refers to the Islamic State, or IS — the armed Sunni fighters who are seeking to establish an independent state crossing the current borders of Iraq and Syria.)

In recent weeks, IS forces have advanced deeper into Syria and overtaken cities in northern Iraq, killing, imprisoning and evicting those who don’t submit to their cause. Kurdish forces in both countries have also been taking advantage of the current chaos to expand their territories. Here, the border between northwestern Iraq and northeastern Syria has effectively disappeared. Alliances are shifting and national identities are being discarded; many are turning to those they fear the least.

This infant's mother went into labor during the YPG operation to rescue Yazidi families trapped on Mount Sinjar. The boy's name is Farman, meaning "the tragedy," says his father, "to remind him of where he came from." (Click to enlarge images)

That night in Siba Sheikh Khidr, Abbas said, he grabbed his Kalashnikov rifle and told his wife to get ready in case she had to leave without him. There were reasons to be fearful. Like most of his neighbors, Abbas is Yazidi. Followers of the ancient pre-Islamic religion, an estimated 700,000 globally, hold a special veneration for a fallen angel, Melek Taus, whose remorseful tears, they say, extinguished the fires of hell and brought the angel back to God. IS fighters and others call Melek Taus "Satan" and Yazidis “devil worshippers.” The Yazidis, like many minorities in the Middle East, have long lived near mountains, seeking safety in their remoteness.

The cell-phone network was overloaded, so Abbas ran to his brother’s house and told him to gather as many men as he could. According to interviews with four survivors, perhaps 1,000 men — butchers, bakers, carpenters, young and old, most of them civilians — assembled near the military checkpoint in Siba Sheikh Khidr to form the only line of defense between IS and the city of Sinjar. Most of the Iraqi and peshmerga security forces that guarded the checkpoint in Siba Sheikh Khidr had fled, survivors said. The only ones who remained were Yazidi.

Abbas, a soldier in the Iraqi Army, and his brother, a member of the federal police, were among them. “We have to build a wall between Daash and Sinjar,” Abbas told his brother, the two of them filling empty rice sacks with stones, which they then used to barricade the road to town.

Of all the bombings in Iraq this past decade, Siba Sheikh Khidr had seen the worst. In 2007, multiple suicide truck bombs killed more than 500 people there in what is considered to be the singe deadliest attack of the Iraq War. After the attack, the Iraqi government constructed a dirt berm perimeter to protect the town, making the only passage to the heartland of the Yazidis a single road. That night, Abbas and the others took positions on the berm around that road, waiting for the IS convoy to arrive.

Top: Driven by Syrian volunteers, a Yazidi family from Sinjar waits to cross the Syrian-Iraqi border. Left: Refugees faced malnutrition, dehydration and death atop the mountain. Right: A member of the peshmerga carries a young girl who lost her parents fleeing IS, near Erbil. (Click to enlarge images)

The IS fighters came in pickup trucks at first — more than 20, survivors said, each mounted with a Soviet-era machine gun known as the dushka. Like many Iraqi civilians, the people of Siba Sheikh Khidr kept Kalashnikovs in their homes for protection. That night, the villagers used them to fire on the incoming Daash convoy, forcing it off the road.

When, after three hours of clashes, Daash pickup trucks failed to break through the Yazidis’ defenses, fighters in Siba Sheikh Khidr said they saw four U.S.-made Humvees driving toward them from the direction of the Syrian border. The armored vehicles had likely fallen into IS hands in June, when the Sunni fighters overran Mosul, Iraq’s second-largest city. “The Humvees ran over our barricade and opened the road for the pickup trucks,” said Faisal Qassim, one of the survivors. “Without the Humvees, we could have stopped them.”

By 8 a.m., after five hours of fighting, the Battle of Sinjar was lost. With no military assistance from Iraq’s central or Kurdish governments, the Yazidis had failed to hold the road and prevent Sinjar from falling to the Islamic State. They had, however, bought their brethren precious time to prepare an evacuation. As the Humvees drove past the barricades and on to Sinjar, Abbas said, survivors from the battle gathered their families and fled. The only way out was up and over Mount Sinjar, a mountain range more than 60 miles long and almost 5,000 feet high.

Tens of thousands of Yazidis would be stranded in there in the coming days, surrounded by IS fighters and facing death from malnutrition, dehydration and exposure. On Aug. 8, the United States launched airstrikes to repel IS forces and dropped pallets of food and water. But it was a group of Syrian Kurdish fighters known as the People’s Protection Units, or YPG, who fought through IS-controlled territory in Syria to establish a safe corridor to rescue many of the Yazidis from the mountain. The YPG fighters are the Syrian brand of the Kurdistan Worker’s Party, or PKK, which has been designated a terrorist group by the United States. They are seeking to establish an independent Kurdish state in northeastern Syria.