Prologue:

Albus Percival Wolfric Brian Dumbledore was angry. Not that it showed. Dumbledore was very good at covering up his emotions. So while Minerva fretted, Severus glowered, Hagrid stared and the rest of the staff reacted in varying degrees of emotion, ranging from shock (Professor Sprout) to glee (Filch) he appeared quite calm. The good natured twinkle never left his unerring blue eyes,and his face remained calm and placid as he seethed.

Dumbledore had shared the letter from the Ministry with the staff mere moments ago, and whilst they processed the news, his mind raced, searching desperately for a solution. The ministry was sending in one of their own as the new Defense Against the Dark Arts teacher. Dolores Umbridge. An idea came to him. Perfect. Dumbledore stood.

"Where are you going?" Minerva asked tightly. He turned, eyes sparkling mischievously.

"To visit an old friend."

Chapter 1

Jack Frost, guardian of fun and prince of mischief (not king, unfortunately, that title went to April Fool) was preparing to strike again. With Baby Tooth's help, his next prank was nearly ready. The Kangaroo would kill him, but it was worth it.

Jack was tying knots in the string when North's booming voice rang out "Jack, come to globe room!" Jack cringed, praying North had no idea what was going on.

"Keep working," he muttered to Baby Tooth, who twittered happily and attacked the net with renewed determination, tiny hands creating knots far more intricate than even Jack was capable of. He dropped from the beam and flew towards the globe room. Jack's heart swelled when he saw the multitude of shining lights on the distant globe. It had been three months since the battle with Pitch and life was back on track, and better than ever. Jack had believers, his memory back, and best of all, a family. He smiled slightly at the thought. Upon entering the globe room, however, he froze.

There was a stranger standing there speaking to North and the others. All the guardians were gathered at the pole for the monthly meeting. They claimed it was for work, but it usually deteriorated into North and Bunny arguing about which holiday was better, Tooth fussing about the sugar in the cookies, Sandy drinking eggnog and getting frustrated when the others didn't notice him, and Bunny nearly killing Jack.

The stranger was a tall old man, with silver hair and a beard to match, so long they could have been tucked into his belt. His face was kind, with sparkling blue eyes peering out from behind half moon glasses. His nose looked as if it had been broken several times. It was his clothing, (and the fact he was a stranger in the pole) that gave Jack pause. The man wore long sweeping silvery blue robes.

Jack eyed him warily. "Ah, Jack, good," North exclaimed, "Now we begin."

"Who is that?" Jack gestured to the man. His face crinkled in a warm smile.

"My name is Albus Dumbledore. I'm the headmaster of Hogwarts" Jack raised an eyebrow, touching down gently and slinging his staff over his shoulder. Sandy flashed some high speed images at Dumbledore.

"Yes, why are you here, at the pole?" North deciphered. Sandy smiled and nodded.

"I'm afraid I need help" Dumbledore explained. "I fear the children at the school are in grave danger, and seeing as its your job to protect the children, I thought you could be of some assistance. If Jack went undercover as a student-"

"Wait, me? At school? No way," Jack interrupted. That earned him frowns from the other guardians.

But Dumbledore merely smiled. "Jack, Hogwarts is no ordinary school. It is a school of magic."

Two hours and a lot of convincing later, Jack had finally 'agreed' to go to the school. So there he stood, weird glowing potion in hand, preparing to disguise himself as a fifteen year old human. He glared, alternating between the blue liquid in the glass vial and the other guardians. Jack took a deep breath. "Here goes nothing," he muttered, and knocked back the viscous potion.

He gagged on the foul liquid, coughing and choking, nearly losing his breakfast. He gasped as his throat burned. It felt as if a rush of molten led made its way through him, followed by a wave of pins and needles. The painful burning sensation died down slowly, leaving Jack weak and shaky. He stood from his doubled over position, leaning heavily on the table. He found himself about an inch shorter than he had been before.

The mini fairies instantly swooned (except Baby Tooth, she seemed immune to all but the most adorable puppy eyes), and a few dropped from the air. He smirked slightly, if shakily, and, with a collective sigh, the last few fairies hit the floor. BT twittered and settled into his hoodie, still unaffected by his human guise, while other guardians stared.

Jack frowned. "What?" He had expected to change a little, sure, but that wouldn't warrant such a reaction from the others. Bunny wordlessly pointed to full length mirror. Jack walked over and looked at his reflection.

A fifteen year old boy stared back at him. He still wore the same clothes, a bit loose now, but the frost patterns had faded. His skin was still pale, but his cheeks were flushed pink. His eyes were a similar striking blue, but flecked with amber brown. His hair was brown too, a few shades off from when he had been human. He groaned internally. The Guardians were protective enough, and he doubted that the new look would do anything to help. He was absolutely correct.