Under one of the shops there's a cellar. In that cellar, there' a book you need to get, protected by a fire trap.
Before I got into the room where the book is kept, the screen started shaking, like an elephant was walking past. When I got into the room, I could see that it was because the fire trap had already been sprung in the cage where the book was kept (causing the shaking with each fire bolt) and the book was not there.
