Problem Child (10th anniversary reissue) by Michael Buckley

This third book in the series takes a dark twist, as Sabrina and Daphne get closer to uncovering the truth about their parents.

Coming face-to-face with their parents' kidnappers, the sisters are stunned when one of them turns out to be the world's most famous fairy-tale character (hint: she wears red) and the other an unstoppable killing-machine known as the Jabberwocky.

Without the presumed-dead Mr. Canis (aka The Big Bad Wolf) fighting at their side, the girls have little hope that they'll ever be reunited with their mother and father.

That is until their long-lost Uncle Jake returns home with stories of a weapon that can kill the Jabberwocky - a weapon so powerful that it had to be shattered into many pieces. Now the girls must find the pieces so the deadly weapon can be reformed.

But to get the deed done they'll have to go head-to-head with the Wizard of Oz, the (not so) Little Mermaid, and even the horrible witch Baba Yaga.

To complicate matters, Sabrina begins to struggle with an addiction to magic and finds herself unraveling a real-life family mystery.