One morning in Asgard, Thor, god of thunder, awoke to find his hammer, Mjolnir missing. Mjolnir was Thor's favorite and most powerful weapon and it's name means Lightning.
Thor searched everywhere. He finally confronted his friend, the god Loki. As Loki is a trickster god Thor figured he may have something to do with this infuriating situation.
Loki swore that he had nothing to do with Mjolnir's disappearance and vowed to help Thor find his weapon.
Though Thor was suspicious of Loki he accepted his help. The two gods went to the goddess Freya for magical help. Freya lent Loki and Thor magical falcon feathers that could change one into a falcon so one could soar above the nine worlds.
Since Loki was already a shapeshifter and experienced in such things he took the falcon feathers and flew down towards the roots of Yggdrasil, the World Tree. The Land of the Giants, Jotunheim, dwelt amongst the Great Tree's ancient roots and was filled with many vicious beings and creatures. Loki was convinced that the Giants of Jotunheim had conspired in the theft of Thor's hammer because it was one of the most powerful weapons in all the Worlds.
Loki shifted back into his original shape when he arrived in Jotunheim and as Loki is a giant himself had no problem entering the hall of the giant king Thrym. When Loki questioned Thrym about Mjolnir the arrogant and vile giant only boasted and told him it was buried eight miles under the earth and if the gods of Asgard wanted it back he would have the hand of Freya, the most beautiful goddess, in marriage for Mjolnir's return.
Thus Loki donned the falcon feathers once again and returned to Asgard with the grievous news. Thor was enraged and Freya so angry that her own hall shook with her rage and her necklace brisingamen flew apart from around her neck.
The gods new a giant's word is only trickery and no god would dare give up Freya in marriage to a creature from Jotunheim anyway. Not that she would allow such a hideous thing.
The gods of Asgard were truly in strife. Tempers boiled. Odin had great patience though and knew one of his sons or daughters would step forward with a plan. This is the way of the Allfather for his wisdom is passed to his children.
The god who stepped forward was Heimdall. With a cool head and unwavering self confidence he put forth a plan to retrieve the hammer of Thor.
Heimdall suggested that they dress Thor as Freya and hand him over to the giant Thrym. As soon as the hammer was revealed Thor was to take it and destroy their enemies.
Thor did not like this proposition as he said the other gods would call him womanlike. Loki said that he would shape-shift and go as Thor's handmaiden. Freya said she would lend him Brisingamen, the beautiful, magical necklace and even after this it took much convincing to get Thor into a wedding dress.
After Thor relented and the plan was in action Thor and his companion Loki were soon tearing through the night air across the nine worlds to Jotunheim drawn by Thor's goats Toothgrinder and Toothgnasher.
Upon arriving in Jotunheim, Thor and Loki were greeted by Thrym and his hall. Their disguises had worked. The giants truly believed that they were accepting Freya and her handmaiden into their company.
A great feast was held before the wedding. Thor ate a whole ox and several whole salmon and drank three measures of mead. Thrym became very suspicious of his bride's appetite. There was much whispering at the table. Loki slipped in and told Thrym that his bride was famished. She had not eaten in eight nights of travel because she was lovesick with the idea of marrying the king of the giants.
In his arrogance Thrym accepted Loki's lie and with Mead flowing through his veins tried to peel back Thor's Veil for a kiss but immediately was startled by the staring red eyes within.
Loki immediately stepped in again and told Thrym that Freya's eyes were that red because she did not sleeping for eight nights in anticipation of the wedding.
Once again the foolish giant accepted Loki's explanation.
A sister of Thrym even had the gall to ask for the rings on the bride's hands in exchange for her friendship and kindness.
Thor could barely contain himself with the anger welling up inside him but kept his cool, Loki was by his side ready to act at any moment that the hammer came in to play.
Finally the feast was done and then it was time for the wedding. By formal tradition a hammer was laid in the lap of the bride for good fertility and fortune. Only this hammer was Mjolnir and the bride was Thor.
As soon as Thor closed his hand around the shaft of his hammer he ripped the veil from his face and immediately crushed the skull of the incredibly surprised Thrym. Next to die was the sister of Thrym who had coveted the rings on Thor's hands.
That night none of the Giants in the Hall of Thrym left that Hall alive and Loki and Thor traveled back to Asgard with news of triumph and another story to tell amongst draughts of honeymead.