The Red Wedding is a massacre during the War of the Five Kings arranged by Lord Walder Frey as revenge against King Robb Stark for breaking the marriage pact between House Stark and House Frey. During the massacre, King Robb, his wife, Queen Talisa, his mother,
Lady Catelyn, and most of his bannermen and men-at-arms are murdered following the marriage feast and bedding of Edmure Tully and Roslin Frey. (From GoT
Wiki)
This scene in the TV show on HBO got a LOT of outcry as it effectively killed off a main story line in the movie and got rid of some of people's favorite
characters.
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