Is when Hilda goes to the Library and stumbles on the arcane book section which was hidden behind a secret passage. She finds a book of spells that the Librarian cautions her on using. She photo copies a spell she thinks may help her friend that is having a string of bad luck. After photo copying the section, she performs the spell. It seems to be working for the friend, so she does it for her mom that's also having some bad luck. Things are going great for them... until this starts happening at random intervals to her mom and friend:
With some help of her elf friend, Alfur, and another friend, they figured out that she didn't read the spell in it entirety; having missing some important footnotes not on the page she copied, they have a limited time to save her mom and friend before Hilda absorbs their souls.