Nate found a brazier and put his torch to it. The darkness receded and he found himself in another cavern but this one was different. It was set up like an open plan office space with makeshift walls and even small four-walled buildings.

It was also the site of a massacre.

"What on...Earth?" he whispered, gazing over the skeletons strewn all about the floor. "What the hell happened here?"

He slowly walked further into the cavern, unable to focus on any specific scene. There must be hundreds of bodies in here. He knelt next to one of the skeletons, it lay face down, a similar Mongol sword lay sticking out of its back. But this one wasn't dressed like a monk, rather it wore chainmail from head to toe, and over that was a white cloak, faded with age and stained with what Nate assumed to be blood. Using his toe, he flipped the skeleton over and saw it was wearing a white surcoat with a distinct red cross

"The Knights Templar?"

He looked around, there were bodies of monks in brown robes and templar knights in their white cloak and surcoats and he wondered if the templars attacked the monks, but if so, why? And how would the monks have fought back?

But then he noticed another skeleton, it had been run through with a spear, the shaft broken long ago but this skeleton wore a different armour. It was made of boiled leather and iron threaded into some sort of fabric, in his hand was a similar sword to the one Nate found upstairs.

Looking around he saw a few more similarly dressed skeletons amongst the monks and knights. They were far fewer of them compared to the monks and templars though.

"Mongols" Nate said. "They attacked the Abbey. But why? Did they know about the jewels?"

He supposed the Mongols didn't need a reason for senseless massacring. They did as they pleased back then. Nate wracked his brain trying to remember when the Mongols attacked Poland. He knew they attacked a couple of times, all of them happening in the 13th century, the first time was around 1240 and the last time was near the end of the century. It all fit in the timeline of when the jewels were taken from Berne Abbey but no clues as to when this specific massacre happened. It didn't exist in history books that much he was certain. If Filip didn't mention it then this was a new discovery.

Nate continued deeper into the cavern, he was walking down an open-air hallway of sorts with rooms on either side, inside of each were more crates and boxes. He entered one of the rooms and found papers scattered around the floor and tables.

Nate picked up some of the pages on the table, they were in better condition, probably due to it being drier in here and some extra insulation being in a room.

He sorted through the dusty, yellowed pages, most of it in written in Polish which he didn't understand, but beneath it all was a large map. It showed an outline of the Tyniec and Krakow area, the Abbey circled. There were drawings from the North and East, arrows in every direction. They were tactics against the Mongol horde, maybe using the Abbey as a defensive position.

Whatever they planned it clearly didn't work. Nate dropped the papers and left the room, continuing down the hall and skirting around the skeletons until he reached the end where it opened up and he found a jail cell at the far end, away from everything.

The cell was a hollowed-out limestone cave with rusty iron bars running from floor to roof. Nate tried the cell door, but it was locked. He tried to peer in but there was only a faint light from the braziers and the torch did little to illuminate the cell. He rattled the cell door, but it wouldn't budge.

He examined the hinges on the cell door and an idea came to him. He put the torch down and walked back amongst the skeletons until he found the shaft of a spear, the spearhead had broken off but that didn't matter. He grabbed a small block of loose limestone and returned to the cell door and put down the limestone block near the cell door and jammed the butt of the spear under the lowest horizontal bar of the cell door as close to the hinge as he could. Using the stone as a base and the spear as leverage, Nate pushed down on the spear shaft as hard as he could.

Once.

Twice.

The door hinges popped up and out and the door fell away with a loud clang that sounded like a gunshot in the vast cavern.

Picking up his torch, he entered the cell and was greeted with a table and three more skeletons.

The first lay in a heap in the middle of the cell, there was a piece of rope around the neck and above the other half hung ragged from a crossbeam above. This one wore the cloak of the templars.

Suicide or murder? he wondered.

The second skeleton, also a templar, was slumped against the wall, Mongol sword thrust through its stomach and Nate wondered if he was left there to die an agonising death.

The final skeleton was dressed in tattered monk robes and was laying on a makeshift cot, hands across the stomach with no noticeable reason for death. Nate wondered if the Mongols just left him in the cell to die, surrounded by the brutal killings of the two templars.

Just as he was about to turn away Nate noticed something on the wall behind the monk. He moved closer and saw there were symbols on the wall, the strokes faded by time but thick and large enough to still make out. They were painted in a dark brown. The symbol was one he knew, one everyone who has an interest in history has likely come across before. It was of a three-sided square, the bottom side missing. A stroke ran diagonally away from the bottom left side of the square and another vertical stroke running up from the middle of the top of the square. There was a waxing crescent moon to the right of it. The flag of the Golden Horde, the Mongol Khanate that conquered most of Eastern Europe from the 13th to the 16th century.

So, the Mongols were here. Did they take the treasure? He brought his torch down to examine to the skeleton and saw something poking out from beneath it.

"Excuse me" Nate said as he pulled the skeleton off the table and letting it fall to the floor with a rattle of bones.

Beneath was a leather folio bag. He picked it up and opened it. Inside were a handful of well-preserved pages and he picked them up and examined them. To his surprise it was written in English, faded but legible.

He began to read.