Sharihan's nightmare started the night of August 3, 2014. The then 15-year-old was at home in Sinune in northern Iraq when her father arrived shaken, shouting that Islamic State jihadists had attacked the south of their Sinjar region, starting a massacre.

"I didn't know what was happening but soon I realised the gravity of the situation", she remembers.

Thousands of people were systematically killed while others tried to escape to the mountains to the north of the city.

"We still had time to reach the Syrian border and reach safety before the Islamist soldiers arrived", she says. "But we were so many that we couldn't fit in the car, so my mother, my brother and I waited at home until they could come for us."

But the roads were later cut off and her father, Xelef, was never able to pick them up.

Instead, they decided to leave for the mountains where there were already thousands and thousands of people in hiding.

"When we left home, there was a red pick-up truck with two jihadists inside waiting for us. My mother begged them to take her instead of my disabled brother and me, but they didn't listen and forced us to get inside", she says.

'The driver stopped and shot her'

Today, Sharihan remembers these events while sitting on the floor of her house, where she came back to live with her father and other relatives last May. By her side, her father listens to her with a blank stare while he smokes one cigarette after another.

"We were taken in the pick-up truck to the outskirts of a city that could be Tal Afar or Mosul.

Sharihan says the last thing her brother said to her was: "Please forgive me." ( ABC News: JM Lopez )

Suddenly, my mum took a gun that she had grabbed from home and shot the man who was beside the driver, killing him instantly.

"Then, the driver stopped and shot her. He violently pulled her from the truck and finished her off by the side of the road," she says, as she covers her face with her hands and begins to cry.

From that moment on, her life was complete agony.

"I can't forget my brother's face at the moment when we were separated. This image remains ingrained in my head," Sharihan says.

"The last thing he told me was to forgive him for whatever was to happen if we were to never see each other again. 'Just forgive me'. He was probably killed that very same day or sometime afterwards."

Forced into sex slavery

Few people have dared to come back to the town and even fewer are willing to tell their story.

Sharihan and her family belong to the Yazidi community that lives in the region of Sinjar. They are about half a million people. Another 200,000 are spread throughout Syria, Turkey and Iran.

This religious minority prays to Melek Taus, an angel represented by a peacock, that is the executor of divine will; the divinity is at such a high level that it can't be directly worshipped. Islamic State (IS) radicals consider them to be satanic worshippers, and their soldiers have the cruellest punishment for this minority.

The fate of captured men was death; many women, mainly teenagers like Sharihan, were forced to be sex slaves for the jihadists. It is thought that between 6,000 and 7,000 Yazidis were kidnapped by IS in the offensive.

During their captivity, the women were raped, abused and auctioned as if they were cattle.

"There, we were forced to take off our headscarves and then we had to walk in front of some men. I was 15. Until that moment, I had never thought that human beings could be sold," she says.

"I don't remember how many men I have belonged to, but at least to 15 people in these three-and-a-half years."

Miscarriage after brutal beating

She was taken to Syria — Raqqa and Aleppo. She got pregnant but had a miscarriage after a brutal beating by her captor when he discovered she was pregnant.

"I spent the days thinking about my family, my brother, what may have happened to my mum's body lying in the road, if animals would have eaten her or if someone would have found her.

I just wanted to be saved or killed somehow".

Trying to regain a 'normal' life

It's now three years after its liberation and Sinjar is still a ghost town. Fear runs throughout its streets and the smell of destruction permeates the air.

More than 70 per cent of its buildings have been destroyed, burnt and looted. Nobody lives here anymore; there is no trace of its 50,000 former inhabitants.

Only an army of cats and some soldiers welcome visitors at check-points at the city's entrance that can only be passed with a special permit.

Those who have returned are trying to regain a normal life, albeit one very different from before the invasion.

Jiyanda says she joined a women-only militant group to, "help the women who have suffered as much as I have". ( ABC News: JM Lopez )

Jiyanda, 18, belongs to the YJS, a military group made up exclusively of women, created to keep the area secure.

She sips a cup of tea in the military headquarters of her unit, one of the few houses still standing.

"When ISIS attacked us, I was studying at school; we had to escape to the mountains with nothing. I remained hidden without food for 10 days," Jiyanda says.

"Then, the PKK [Kurdistan Workers' Party] opened a passage and we could cross into Syria. We stayed in a refugee camp there. The conditions were terrible and my one-year-old sister died.

"Years went by and I thought I had to do something. That is why I enlisted, to help my people and the women who have suffered as much as I have."

Remains of human skulls and clothing lie in a mass grave where it's believed at least 68 women are buried in Solakh, south of Sinjar. ( ABC News: JM Lopez )

A long way from peace

For Sharihan, time passed mercilessly until one day she found a mobile phone and contacted one of her brothers. After establishing contact, the member of Jabat al-Nusra who kept her in Idlib agreed to sell her for $13,000.

When she got back home, she weighed just 30kg and was physically and mentally destroyed.

She thinks her childhood is lost forever and that this will be her only experience in life. She needs psychological help, but rehabilitation programs have not reached everybody.

In their empty living room, a Kalashnikov propped against the wall is a reminder they are still a long way from peace.