It was September 6, 2018. The two Saudi sisters were on a family vacation in Colombo, Sri Lanka. For weeks, they had helped their mother organize the trip, feigning excitement at the possibility of two weeks away from Riyadh, but knowing that if all went to plan, they'd never go back.

Failure was not an option. Every step of their escape from Saudi Arabia carried the threat of severe punishment or death.

"We knew the first time, if it's not perfect, it will be the last time," Reem says.

CNN has changed the sisters' names and is not showing their faces, at their request for their safety.

The sisters say years of strict Islamic teaching and physical abuse at home had convinced them that they had no future in a society that places women under the enforced guardianship of men, and limits their aspirations.

"It's slavery, because whatever the woman will do it's the business of the male," Rawan says.

That's why they say they renounced Islam.

And that's why aged 18 and 20, they stole back their own passports, hid their abayas under the bedcovers, snuck out of their holiday home and boarded a flight from Colombo to Melbourne, via Hong Kong.

The Hong Kong stopover was supposed to take less than two hours.

Two hours has turned into five months.

This photo was taken in a restroom in an airport during a trip to Turkey. The sisters wore this type of niqab when they were traveling outside Saudi Arabia.

Why they fled

"Good girls" do what they're told, are quiet, don't argue or risk embarrassing their families. Reem and Rawan say they had turned being "good girls" into a fine art.

"In our house, we (were) always the good girls they wanted us to be. So, if they want us to clean, we will clean. If they want us to cook, then we will cook," 18-year-old Rawan says.

"The last two years it was really bad, because I just forget who I am, I am just pretending (to be) like an Islamic girl," says her 20-year-old sister, Reem.

They went to school, studied hard and avoided confrontation. Of course, the same rules didn't apply to their brothers. Beat your sisters, the siblings say their brothers were told, it'll make you better men.

Reem and Rawan are reluctant to talk about the abuse at the hands of their family. They say it didn't happen all the time, just enough to remind them of the rules. And enough to fill them with terror about what might happen if anyone found out about their plan or, worse still, caught them carrying it out.

The escape

Leaving Saudi Arabia is not a simple undertaking for women who rebel against the system. Permission is needed from a male guardian for many basic activities, including international travel.

Reem and Rawan say they had been planning their escape in secret for two years. They didn't dare discuss it in case they were overheard, so, instead, they swapped WhatsApp messages, even while alone at night in their shared room.

Before they fled, the Sri Lanka vacation was just like any other. They wore their niqabs to the beach and sat away from the surf while their brothers swam and joked. They cooked the meals and spent most of their days inside. It was humid. Their niqabs stuck to their skin and made it hard to see.

"We travel to move from a box to another box. From home to hotel, nothing will change," Rawan says. "They will go out, they will live freely, the men, of course, we will sit away, watching them doing what they want."

Their five-year-old sister played in the sand, but their 12-year-old sister, like them, didn't. She too was learning that it's OK to be a girl in Saudi Arabia -- until you grow up.

During the trip, Rawan turned 18. The timing was no accident. The vacation was planned with gentle persuasion to coincide with a birthday that, unbeknown to their mother, allowed Rawan to apply for an Australian tourist visa.

On the last night of the trip, the sisters launched into action. Reem pre-booked the taxi. It was Rawan's job to retrieve their passports from a bag stored in their parents' bedroom. Around 2 a.m., she tiptoed past them as they slept, took the bag with their passports, then snuck back in again to return the bag so as not to raise suspicion.

"It's a really great memory, exciting," Rawan tells CNN, smiling. Of the two sisters, she's the more talkative, taking the lead and occasionally looking to her sister for advice on the right word in English. Reem is more reserved. She's careful about what she says and who to trust. They both have dark, short, curly hair and being small in stature seem much younger than their years.

When the cab driver arrived at 5 a.m., the sisters say they did something they'd never done before. They pulled on jeans they'd bought in secret and walked out of the house without their abayas.

It was only after they arrived at Colombo Airport that the sisters booked the flight they'd meticulously researched online: SriLankan Airlines flight UL892 departing Colombo at 9 a.m., arriving Hong Kong at 5:10 p.m. local time. From there, they'd take Cathay Pacific flight CX135 departing at 7:10 p.m. for Melbourne, Australia.

They had no trouble boarding the plane for the roughly six-hour flight to Hong Kong.

It was after they arrived at Hong Kong International Airport that things started to go wrong.

The younger sister takes a selfie in a hotel room. They say they felt like "ghosts" under the full-length black robe, as if they were invisible, not there.

Arriving in Hong Kong

What happened in the transit area was something the sisters might have anticipated had they known their uncle had connections to the Saudi Interior Ministry or had realized the power Saudi officials could have over local airport staff.

As soon as the women stepped off the plane, they say two men approached them and asked if they were going to Melbourne. The women say the men asked for their passports and boarding passes, first saying they might miss their flight, then suggesting there was something wrong with their Australian visas.

In a letter to the sisters' lawyer obtained by CNN, SriLankan Airlines has identified the men as Naeem Khan, SriLankan Airlines station manager, and Noman Shah, a staff member for ground handling agent, Jardine Aviation Services.

The sisters say the men led them to another area of the airport, where their lawyer Michael Vidler says they canceled the women's Cathay Pacific flight to Melbourne and booked them, without their knowledge, on an Emirates flight to Riyadh, via Dubai.

Cathay Pacific tells CNN that the sisters' flight was canceled by representatives of SriLankan Airlines.

SriLankan Airlines told CNN its staff members canceled the flight at the "explicit request" of the Saudi Consulate, which had already booked the sisters on the flight to Riyadh.

The airline said consular officials told its staff the women's father had phoned and said the sisters needed to go back to Saudi Arabia "as soon as possible" as their mother was terminally ill.

The women knew their mother wasn't ill and were quite sure there was nothing wrong with their visas.

"We allege that they were the subject of an attempted kidnapping in an international airport in a restricted area," Vidler tells CNN. "The Saudi Consulate was actively trying to deceive them."

CNN has approached the Saudi Consulate in Hong Kong and the Saudi Foreign Ministry for comment on the sisters' claims and has not received a response. Hong Kong Police have confirmed that they're investigating the allegations.

SriLankan Airlines says at no time did the sisters indicate there was a problem. The women disagree.

Vidler says that closed-circuit television seen by his team appears to confirm that Saudi Consul General Omar Al Bunayan was at the airport, speaking to the women and airline staff.

The presence of senior Saudi officials at the airport filled the women with dread. They'd heard about Dina Ali Lasloom, the 24-year-old Saudi woman who was forced onto a plane to Riyadh at Ninoy Aquino International Airport in Manila in April 2017. Her hands, feet and mouth had been bound with duct tape, one witness told Human Rights Watch.

Reem and Rawan feared the same could happen to them.

They excused themselves to go to the bathroom where they made the decision to flee. As they emerged, they said they saw one of their passports on the table. Rawan tried to grab it.

The teenager says one of the men immediately slapped her hand, prompting the sisters to scream in Arabic, "You kidnap us!"

The sisters say they caused such a scene that the Consul General suggested they move to a quieter area where he presented them with their passports and new boarding passes -- for Dubai.

They ran. First to the Cathay desk where counter staff told them their flights had been canceled. Then to the Qantas desk, where they'd hurriedly booked the next flight to Melbourne, QF30, departing at 7:00 p.m.

Soon after they were issued boarding passes, the women say Shah, the ground handling staff member, tried to snatch them.

Jardine Aviation Services, whose staff members carry out a number of tasks within the airport, says its employees didn't tell the women their mother was ill or that was there was an issue with their Australia visas. It denies its staff members slapped Hawan's hand or tried to grab the sisters' boarding passes.

Hong Kong's Airport Authority has refused to give CNN a closed-circuit recording of the events that unfolded due to privacy concerns.

The women shared selfies they'd taken of their life before they fled. They wore niqabs in public from the age of 11 and at home were told to wear long gowns, so as not to tempt their brothers.

For the second time in two hours, the sisters say senior Saudi officials stopped them from flying. The sisters say Saudi Vice Consul Al Sharif told staff at the Qantas check-in desk they were running away, had stolen money, and weren't tourists.

Australian immigration officials were summoned on the phone and after a conversation with the women, Canberra canceled their visas.

"The only issues with the visa occurred when the Vice Consul made what we believe to be false representations to the Australian authorities at the boarding gate of Qantas airlines," Vidler says.

A spokesperson from Australia's Home Affairs department declined to comment on individual cases. Qantas also declined to comment but a spokesman pointed out that the airline does not make visa assessments.

The sisters say they stayed at the airport for three hours before asking Cathay Pacific counter staff for permission to leave. They wrote their names and a fake Hong Kong contact address then caught a train to the city.

Khashoggi case puts Saudi Arabia under scrutiny

Reem and Rawan escaped Saudi Arabia weeks before the world's attention turned to the kingdom and the disappearance of Washington Post columnist Jamal Khashoggi. They watched from Hong Kong as gruesome details emerged of Khashoggi's murder inside the Saudi Consulate in Istanbul, allegedly by a team of hitmen who cut up his body with a bone saw.

In November, a source told CNN that the CIA had determined that Khashoggi was killed on the instruction of Saudi Crown Prince Mohammed bin Salman bin Abdulaziz Al Saud, known as MBS, a claim the kingdom denies.

The Saudi sisters shrug when asked if they are surprised by Khashoggi's murder and the allegation that their country's de facto leader ordered it.

"We know that Saudi Arabia can do stuff like this," Reem says. "They are chasing innocent girls, not even important girls," Rawan agrees. "We're just normal young women trying to find a life far away from violence."

Soon after the women arrived in Hong Kong, their father and uncle came to the city to find them. Hong Kong police confirmed to CNN that a missing persons report had been filed.

Using a passport tracking system linked to hotel check-ins, Hong Kong police officers located the sisters on Monday, September 10 and took them into custody for questioning.

The women say they were held in a room in the imposing Wan Chai police headquarters for six hours, where they repeatedly refused requests from their father and their uncle to see them.

Police eventually drove them back to their hotel. By that time, it was after midnight and the women hurriedly packed their bags and fled.

In the five months since, they've moved from shelter to shelter, hotel to hotel, to evade detection and their potential forced return to Riyadh.

The sisters have not sought asylum in Hong Kong, however. Doing so would have put them at the end of a long queue of claimants caught in Hong Kong's Unified Screening Mechanism (USM), a system used by the government to process asylum claims. The UNHCR doesn't assess claims in Hong Kong.

Through their lawyer, Reem and Rawan are seeking a visa in a safe country. Vidler says they have few options. Their Saudi passports have been canceled and they don't have formal permission to stay in Hong Kong.

The sisters say being forced to wear the niqab robbed them of their identities. They knew they'd be expected to wear one for the rest of their lives, like their mother.

Life in Saudi Arabia

At home in Riyadh, the sisters say they were beaten by their father and brothers "for a reason and no reason."

One day when she was 14, Reem says her brother started hitting her for talking and laughing with Rawan. "He said that people will hear my voice and it will bring shame," she says.

The sisters knew it was likely there would be an arranged marriage. There was talk of Rawan marrying her younger cousin, a boy still in high school.

Reem was the first to renounce Islam in October 2016, followed by Rawan in May 2017. They didn't dare tell anyone but say they announced it under fake names on Twitter.

"I knew If I told my family they will hurt me and I'll be killed. Because that what we studied in schools, that whoever left Islam should be killed. I knew no one will protect me because all my family are so religious and none of them will support me. I was afraid of them finding out," Reem says.

There are no firm figures on how many Saudi women have escaped the country -- or how many have failed in their attempt to leave -- but the total number of Saudi asylum seekers is rising.

According to the United Nations, 575 Saudi nationals applied for asylum in 2015. Two years later, that figure had more than doubled to over 1,200.

The period coincides with the rising influence of MBS who in June 2017 was appointed heir to the Saudi throne by his father King Salman.

Since then, MBS has made it clear that dissent won't be tolerated, even as the kingdom has earned international plaudits for new female-focused policies, including lifting the ban on women drivers.

Rana Ahmad, a 33-year-old Saudi national who runs the Atheist Refugee Relief agency in Germany, says the jailing and torture of the same women who campaigned for the right to drive had sent a message to some Saudi women that they have no future in the country.

"They look at these women, they're trying to do something and the government puts them in jail. So they see no hope anymore, they want to leave," she said.

Adam Coogle, a Middle East researcher for Human Rights Watch (HRW), says women whose escape plans are thwarted are at serious risk of abuse.

Punishments range from being locked in their room for months on end or banned from using a mobile phone, to criminal prosecution by the state for disobeying their parents or harming the kingdom's reputation. The women themselves say they fear they'll be killed by their own families.

Coogle says there are few safe corridors for women to leave, because of political pressure the Saudi government applies to some foreign countries to return "runaways" without giving them the opportunity to claim asylum or put their case forward.

"Anywhere you go that doesn't have some sort of respect for refugee law or a strong record of rule of law is a problem because they're the countries where Saudi Arabia can apply its diplomatic pressure to get countries to cooperate," he says.

Few regrets

Reem and Rawan say they could see signs of change in Saudi Arabia, but it wasn't moving fast enough for them. They laugh at the suggestion that progress was made by giving Saudi women the right to drive.

"Driving cars is not something to celebrate," Reem says. "There is a woman abused in the house, and no one hears their voice, and they want us to celebrate a car?" Rawan adds.

In Hong Kong, the sisters watch Netflix to pass the time. Wearing jeans and trainers, they could easily be mistaken for one of the millions of tourists that come through the city each year.

Sometimes Reem wears lipstick. She seems relaxed but has a habit of picking at the skin on her fingers when she's nervous. Sometimes, she does it so much that they start to bleed.

The sisters are anxious about what comes next. But even after five months of uncertainty and fear, they have few regrets.

"I regret not waiting, but not leaving," Reem says. "From my childhood, I knew this is not my home. I always knew my rights would be taken."

Rawan says she too knew there was no life for her in Saudi Arabia.

"When I was growing up I saw my brothers do whatever they want, have whatever they want. But for me, I should be a good girl, a good woman, to marry someone, my cousin, because I should not even dream to choose my husband, to choose my partner.

"I want to study what I want, I want to work what I want, I want to choose the day I marry. To choose the man I marry. Even if I don't want to marry, I want the right to choose."

Correction: This story has been updated with new information from human rights lawyer Michael Vidler who said he originally misspoke about which Saudi consulate official was at the Hong Kong airport speaking to the Saudi sisters and airline staff. Only the Consul General was seen by Vidler's team on closed circuit television.