Queen Guinevere is a character on ABC's Once Upon a Time. She debuts, with her first appearance, in the second episode of the fifth season. She is the wife of King Arthur and rules alongside him in Camelot.
Before the First Curse
As a young Arthur and Guinevere walk in Camelot, he tells her of how he will one day be king. They walk to a tree and Arthur informs her of how Merlin is trapped within the tree and his dream in which Merlin told Arthur a prophecy where he would pull a sword from a stone and become king. Arthur tells her she will be his Queen. After some discouraging words from Kay, she tells him to follow his heart.
Before the Third Curse
When Emma, her allies and Zelena arrive in Camelot, King Arthur introduces his wife Guinevere to the, who welcomes them to the castle. They hold a ball in honor of the arrival of the Savior (who Regina claims to be), as it was prophesied that they will be the one to free Merlin from the tree. At the ball Guinevere, along with everyone else witnesses Sir Percival killed by David after he tries to kill Regina. After the aftermath Guinevere tells Arthur that the new guests frighten her and is scared as to what other troubles they will bring. but Arthur tells her that they are the only hope of freeing Merlin and finding the missing piece of Excalibur.
After David "loses" the toadstool that was meant to be used to contact Merlin with, Arthur reveals to Guinevere that he stole it from him.
After the Third Curse
After Emma curses everyone back to Storybrooke, Guinevere arrives with no recollection of how she arrived. She is reunited with Arthur, but shocked to find that Excalibur has gone missing. David informs them that if it's in Storybrooke, they'll find it.