This is the true story of the theft of Mjolnir. One night Thor and I had a little drinking contest. When we awoke with the bright light of morn, Mjolnir was nowhere to be found. Thor alternated between bellowing his fury and holding his head and moaning. T'was comical, or it would have been if his bellowing weren't making my head ring. All his carrying on brought Loki around to see what was the matter.
"Mjolnir has been stolen!" Thor thundered. Loki soothed him and then asked, "Where have you looked, nephew?" This drew a whole new round of curses from Thor. Looked? He hadn't looked. He just woke and started bellowing. HA!
Loki told Thor that he had an idea and helped him away. We found out later at the Thing that they had gone to see Freyja and borrow her feather cloak, or to hear her tell of it Thor demanded it. However it all happened, Loki ended up with it and flew through the worlds searching for Mjolnir. Eventually Loki found the hammer in Jotunheimr. After long negotiations, Thrymr will only agree to return Mjolnir to Thor if he is given Freyja to wife. He was so smitten with her that he didn't care that she already had a husband, dismissing Oor as a god not worthy of her. When Loki delivered the news to Thor and Freyjr, Thor told Freyjr to ready her wedding dress and get going so that he could have Mjolnir back. Her fury must have been a sight to see because she was still so mad at the Thing that she snorted so hard she broke her necklace, letting Brisingamen fall.
And so, we came together in the Thing to discuss how to get Mjolnir back from the Jotnar. We were all still a little sore in the head, and Freyja's angry tones were ringing like church bells. I opened my mouth and out it came, "Why doesn't Thor dress up as Freyja and go get Mjolnir himself if it matters that much to him! He can wear the dress and the head-dress of a bride to hide his face. If he wears Freyja's jewels and Brisingamen, they will assume he is Freyja."
Dead silence while it all sank in, then Thor exploded. "Heimdallr, you idiot! I am not about to dress as a woman. That plan is the dumbest thing I've ever heard. Who would believe the mighty Thor is a woman!?!" "You do realize that if we don't go to claim Mjolnir soon, we'll have Jotunn for neighbors." Loki said. "I'll dress as your maid and accompany you." Working his magic, Loki convinced Thor that he was, after all, the only one who could do the job right. A message was sent to Thrymr to prepare for his bride.
The goddesses, especially Freyja, had a grand time dressing Thor as a bride. They went all out decking him with wedding finery and jewels and a head-dress fit for a goddess. In the morning Thor and Loki headed for Jotunheimr.
Thrymr was thrilled to see the chariot arrive. He offered a hand to his blushing bride, but she stepped down herself. Thrymr failed to notice the carriage's visible lurch as his 'delicate' bride left the vehicle followed quickly by her maid. They proceed to the wedding feast. Thrymr was a bit started by his bride's appetite. She, in fact, ate more than some of his best warriors and she drank them under the table. Thrymr questioned his bride, but Loki jumped in explaining that she was so excited she hadn't been able to eat or drink since she heard she was to marry. Thrymr looks a bit doubtful but accepts Loki's explanation. That is, he accepted it until he leaned over to sneak a kiss from his bride. Placing Mjolnir in her lap as a bridal gift, he lifted the veil to see...Thor. Thrymr jumped back about 20-feet, but that didn't save him. Thor, Mjolnir in hand, slaughtered all who attended the wedding feast.
Thor, triumphant, returned home. That night, over mead, Thor slaps me on the back and says, "Heimdallr, that wasn't such a bad idea. I pulled it all off brilliantly." We toast his bridal gift.