Written for the_alchemist in the 2011 Ides of April exchange. I have revised the story somewhat from the version originally posted for the fanfic exchange.
One day it happened that the King of the Fairies and his servant wandered through the fields of France. "A plague light upon these mortals," said Oberon darkly, "French and English both. They have plowed up our fairy rings with their horses' iron-shod hooves and trampled the flowery banks wherein Titania delights."
"Shall I plague them for you?" Puck asked hopefully. "For want of a horseshoe nail -–"
"Let be," Oberon said curtly. "I am not in a jesting humor. Let us leave this place, for it gives me no pleasure to see the fair fields soiled with blood."
At that moment, a maiden came fleeing from the direction of the castle. She was richly dressed, as one of noble birth, and her woven locks were disarrayed by the haste of her flight. She stopped to catch her breath and looked back fearfully.
Oberon made himself invisible with a gesture. "Another cruelty of these mortals," he said. "Robin, daze her pursuer's wits so that he may not find her."
"I would, my lord," Puck returned, "if he had any wits to lose —"
"No jesting, but obey me."
The lady's pursuer, an English soldier, was not far behind. He reached out to seize her with a triumphant smile. Before his hand could grasp her sleeve, Puck cast a mist over his senses. The soldier staggered, rubbing his eyes. Without hesitation, the young noblewoman seized the soldier's dagger from his belt and stabbed him through the heart. He fell to the ground, bleeding out his life.
Puck tilted his head to look at her better. "A spirited maid," he said. "Would it not be shame, my king, for her to fall into the hands of some ruffian after we have gone?"
Oberon looked at him suspiciously. "Robin, what mischief wilt thou make?"
"No mischief," Puck protested. "Only a simple trick that can do harm to none."
"Do not meddle in these wars between mortals," said Oberon sternly. "But save the maid, if thou canst do it without violence."
Puck cut a caper. "Not the least harm, I assure you! Not so much perdition as an hair."
Oberon drew his cloak about him. "I will stay here no longer. When thy task is done, join me without delay."
"I hear, my king. Your servant will obey."
Puck considered the maiden. She retreated into a nearby clump of trees and crouched down to hide. Well enough, she would stay where he left her.
He grasped the mane of a riderless horse and hopped to its back, clinging like a burr. The horse rolled its eyes and frantically tried to shake off the weight it could feel but not see. Perched on the maddened animal's back, Puck laughed heartily to see the soldiers of both armies scatter frantically out of his way. It would be better, Puck thought, for the maid to be the prisoner of a nobleman, so he ranged about until he found one. The Earl of Suffolk was nearest to hand. Making his voice like the Duke of Alençon, Puck called out: "English coward! Are the English only brave in numbers? Fear'st thou to face my single sword?"
Suffolk drew his sword and looked about him. "Where art thou, French villain? Stand and face me!"
In a short time, Puck lured Suffolk to the grove where the noble maiden was hidden. Puck stretched out comfortably on a sturdy branch of an oak tree. As Suffolk stepped through the screen of trees, Puck leaned down and squeezed the juice of a magic herb into his eyes.
The Earl looked around him in a daze. His eyes lighted on the maiden. To Puck's great amusement, Suffolk began babbling poetic endearments, mixed with words of reassurance to his prisoner. The love-struck nobleman ended his speech: "Who art thou? Say, that I may honor thee."
The maiden looked at her captor mistrustfully. "Margaret my name, and daughter to a king."
Puck hopped off lightly to seek his master, certain that Oberon would be satisfied. The maid was safe, and he had done no harm whatsoever.
"Not so much perdition as an hair." From The Tempest.
"Who art thou? Say, that I may honor thee." / "Margaret my name, and daughter to a king." From Henry VI Part 1.