In Auntie Ethel's lair. I've just defeated her. She's offering me an ability score increase in exchange for the girl.
Obviously I choose the power. However, after the cutscene, Auntie disappears in a puff of green smoke and the game crashes.
Luckily I had dinner during the fight so quicksaved, which I've been able to load back into near the end of the fight. Each time when making this deal, the game crashes - I've tried 5 times now. It's only with this option, though, as if I choose to save the girl it doesn't crash - which is an option my character would rather not take.