Ket is a disaster of a witch, and admits it freely. She can barely tell mint from mugwort, the crows that flock around her refuse to engage in proper conversation, and she's as likely to trip over her own feet as cast a proper spell. Rediya, on the other hand, is everything a witch should be - elegant, competent, mysterious, and not at all likely to fall flat on her face halfway through enchanting her house not to fall down around her ears.
When Rediya needs a place to stay while she hides from the Baron's soldiers, Ket is more than happy to oblige. And when she needs a little help finishing what she's started, well... Ket never liked the Baron anyway.