Author's note: Thank you to Green Phantom Queen for her collaboration with me on this story! :)

Prologue: The Music

Mokuba Kaiba opened the back door of the black limo. He swung his backpack off of his shoulder and placed it down onto the seat, then went inside and slammed the door shut behind him. "Kaiba Corp, please," he told the driver.

The limo started speeding away in the direction of the Kaiba Corporation building. Mokuba knew his brother wouldn't be there for another hour or so, since he was still in school, but he couldn't wait until he came home. He'd gotten a perfect score on the test he'd taken a couple of days ago, which made him absolutely ecstatic and eager to show his brother the paper. It almost seemed like after that, nothing could spoil his day.

Smiling and leaning back on the seat, he reached over and pressed a button on the side of the limo door which made the window go down. He sighed as he let the gentle breeze wash over him.

Suddenly, the faint notes of a strange melody started coming into the limo, carried by the wind blowing inside. Mokuba opened his eyes upon hearing the music and leaned towards the window to try and discern the familiar sounding tune. As he listened closely, he realized that it sounded like that calliope music which played at carnivals and such all the time.

He closed his eyes again and started rubbing his forehead as the music grew louder and louder. He'd suddenly gotten a strange headache at the sound, and he started to groan in slight pain. "Uhh…" he murmured.

When he opened his eyes, he saw the source of the music riding in the street next to the limousine. It was a wooden circus wagon painted in traditional colors of red and white, with a top made to look similar to a circus tent, pointed upwards and with a red pennant and megaphones blaring out the circus music on its tip. Written on the side of the wagon in large, black and gold letters were the words Cirque du Shadows.

Drawing the wagon itself was a man riding a large, black horse decorated with a golden feather perched on its head, golden bridles, and a gold saddle. The man himself was wearing a black, shiny top hat, a red coat with yellow buttons and tails, a white vest, black pants, and black shoes. Clutched firmly in his hand was a coiled-up black whip. He looked rather sinister with his slicked-back black hair, piercing black eyes, and a long, black mustache curled up at its ends.

Mokuba blinked. He didn't know why, but all of a sudden he had an extremely strong urge to get out of the limo and go towards the circus wagon. He called up to the driver, "Stop!"

A bit shocked by the sudden outburst, the driver quickly slammed his foot onto the brake, bringing the black car to a screeching halt.

Mokuba opened the door and jumped out of the side the circus wagon was on, slamming it shut behind him. The ringmaster, upon seeing Mokuba come out, pulled on his horse's reigns and made it come to a halt.

Mokuba turned, stuck his head in through the open window and said, "You can drive back to Kaiba Corp alone; I won't need the ride."

Confused but compliant, the driver pushed down on the accelerator and the limo sped off down the street.

Mokuba turned and looked up at the ringmaster, who gave him a rather sickly sweet smile. "Hello there, my child," he said. The ringmaster got down from the horse's back and walked up to Mokuba. He held out a white-gloved hand towards him. "Why don't you come up and check out what I've got in my wagon? You'd like to see what sorts of secret, hidden things go on outside of the actual circus, wouldn't you?"

For some reason, Mokuba didn't feel nervous or hesitant about going with him. In fact, he was practically drawn towards him. "Sure, I'd love to," he smiled. He took his hand and let the ringmaster guide him around to the back of the circus wagon.

At the back of the wagon, two red-painted wooden doors had been sealed up firmly with a chain and padlock wrapped around their handles. The ringmaster pulled out a large metal key on a ring from his jacket pocket and placed it into the lock. After a turn and a small click, the padlock snapped open. He pulled the chain off from the doors, grasped one at its handle, and pulled it open. "Do come inside, look around."

Mokuba climbed up into the wagon, with the ringmaster right behind him, smiling devilishly.

After a little bit of time, a bright flash of red light suddenly came out through the slightly open doors of the wagon. The ringmaster jumped back out of the wagon and slammed the door shut. He quickly took the padlock and chain and snapped it back around the handles, sealing the doors up tight.

"Now don't you try and go anywhere, little guy," the ringmaster called inside. "As of now, you are the property of Ringmaster Yingya."

With that, he walked around the wagon and got back up onto his horse. "C'mon, Umakuro-let's go and set the circus up. So many mortal children to bring here, so little time…"