Marnie, with the Shoebox Zoo animals in tow, travels from Edinburgh to her hometown of Denver. Now accompanied by her best friend Kyle, the quest for the Book of Forbidden Knowledge continues as the two friends must piece together several clues in order to find the true location of the book, all the while having to once again stop the evil plans of Toledo, who is seemingly back from the dead as a ghostly apparition. Will Marnie and Kyle be able to find the book and turn the Shoebox Zoo back to their human forms? Or will the nefarious shapeshifter prevail?

On her 11th birthday, Marnie McBride goes to a junk shop with her father to pick out a present. There, the mysterious shopkeeper eagerly gifts her a shoebox containing four animal figurines, all of whom have the ability to magically spring to life. Marnie now has to deal with the struggles of balancing her life between adventuring with the collectively named “Shoebox Zoo” animals on a quest to find an ancient book of magic, and her day-to-day life as a schoolgirl, on top of having to deal with the grief stemming from the loss of her recently deceased mother.