Without a doubt the most well known story about the Nordic gods, mainly because it’s one of the first children are taught.
A jotun stole Thor’s hammer, and refused to give it back unless he got the goddess of love, Freya, as his wife. When Thor told her to get in her wedding dress and go marry the jotun, she got so angry that the whole world shook so they had to find another solution. Finally it was suggested that Thor dressed up as Freya instead. Thor of course protested but Loki, who apparently always thought men in women’s clothes was an awesome idea, convinced Thor by saying “And of course I’ll come with you as your brides maid” But Thor made an awful woman, and Loki had to save his ass time and time again and had to come with weak excuses as to why “Freya” was acting so manly. Finally Thor got his hammer, had a massive hissy fit and went home.
In this version however, it’s the owner of a drag club who has the hammer, so Thor and Loki has to dress up to sneak in and have a look around (Well, they didn’t have to be in drag, but Loki said they did and Thor had never been a place like that, so he just trusted Loki).
There are a couple different interpretations and studies on the stories. People are still going over them to this day trying to get the stories as accurate as possible. The most popular versions seem to be Snori's versions, but the problem with that is that Snori was a christian lawyer (from my understanding) who put his own christianized twist on the stories, demonizing Loki more than necessary. Not that I have anything against all christians! It's just... there is much more to it than what Snori wrote. I hope you can find a couple different books with different interpretations to better help you piece it all together. The stories are very amazing and entertaining.