Sir Kay has Spell Cast on Him
A farmer tending his fields on a fall afternoon found a knight wandering around apparently in a daze. The farmer approached him and asked the knight who he was. The knight only kept repeating the name "Baba Yaga" over and over. The farmer didn't know what to do so he brought the knight to his lord's castle.
The lord, Sir William of Lancashire, recognized Sir Kay immediately since he made frequent visits to Camelot on business. Sir William stated that Baba Yaga was a witch in the vicinity who had a bad reputation for casting spells on people who got lost and unfortunately approached her hut.
Sir Kay was sent back to Camelot where, Merlin, is trying to undo the spell.