Little Kinsley Vance and Allara Shaw were inseperable when they suddenly vanished at school 21 years ago.

The nine-year-old girls were last seen together at their annual sports day. But by the time the school bus arrived at 3.30pm, they had both disappeared.

Their fate remained a complete mystery for years, leaving their small community desperate for answers.

The girls' families never gave up hope; Riley Vance, Kinsley's mum, spent years searching, hiring private investigators and following up on countless false leads. Odette Shaw, Allara's mother, eventually left town, remarried, and tried to build a new life. But the pain never faded.

Then in July 2012, a fire ripped through a remote farm on the outskirts of town. When firefighters put out the blaze, they unearthed a strange metal hatch, hidden from public view for decades.

Underneath the hatch on the farm in Willow Creek, Iowa, was a bunker, which contained two rusted cots, stained mattresses, piles of empty canned food containers, and a pink child's shoe with a butterfly decal - it had belonged to Kinsley.

On the concrete wall, there were childlike drawings: a sun, a house, and two stick figures labeled 'K' and 'E', US Today reports. It was clear the two girls had been held there.

Forensic analysis revealed that the bunker had only been used for a few months and then abandoned. The dugout's origins were traced to the Cold War-era; it had been built decades earlier and forgotten, a secret even the current owner didn't know.

It suggested someone local to the area. Warren Finch, a retired school janitor, had recalled seeing Kinsley and Allara exit a side door on the day they disappeared, heading toward the car park with no signs of struggle or screams. It seemed likely the abductor was also someone they trusted.

Kinsley's mum Riley was quick to act. She cross-referenced school activity rosters, church directories, and farmhand lists - and one name stood out: Gideon Pratt, a quiet Sunday school teacher Kinsley loved, and who had also worked periodically on the farm.

Riley was able to confirm Pratt's seasonal work at the farm and his knowledge of its remote corners. Further investigation into his last known residence revealed survivalist manuals: How to Disappear Completely, Wilderness Survival Skills, and The Complete Guide to Off-Grid Living, US Today reports.

It then emerged that he had abruptly left town in late 2004 - the same year the two girls vanished - claiming he was leaving to do missionary work.

Riley now had a new theory. Pratt hadn't been following a religious path, he had been preparing for a life off the grid. She believed that Pratt was living in isolation, and must be making large, infrequent cash purchases at remote general stores.

She combed through transaction records, searching for a pattern. And then she found it - semiannual bulk purchases of food, propane, medical supplies, and feminine hygiene products, being made in Missouri's Ozarks.

Riley presented her findings to Detective Miles Corbin, but jurisdictional complications slowed the process down. So the determined mum drove to the Ozarks herself.

Her search led her to a cabin deep in the woods - and there she saw something incredible. Her daughter Kinsley, now 17, looking gaunt but very much alive.

Pratt then emerged, armed, and a terrifying confrontation followed. Riley pleaded with Kinsley, as Pratt tried to drag the teen back inside the cabin.

But in a moment of clarity, Kinsley struck him with a piece of firewood, giving her mum the chance to seize his rifle. Mother and daughter fled through the woods, escaping to safety.

Riley called Corbin, who arrived with a tactical team, and Pratt was arrested at the scene.

Kinsley was taken to hospital, malnourished and deeply traumatised. She was then able to reveal the fate of her beloved friend Allara.

The teen shared that her best pal had died of illness in the bunker just months into their captivity. Their abductor refused to get the girl medical help and Allara was buried in the woods nearby.

Pratt was extradited to Iowa and convicted of kidnapping, murder, and years of abuse. He received multiple life sentences without parole.

Two best friends vanish at school - 8 years later a fire reveals horrifying truth - The Mirror