The Magical Detectives — Brian Keaney

When Otto returns home from school one day to find his mother missing, and then discovers an advert for the Magical Detective Agency, he decides there's nothing for it but to call on their services. In fact, the agency is just one man, a strange character call Maximillan Hawksmoor, who becomes convinced that Otto's mother has been abducted by Elementals - beings who live in a completely different world. It's not long before Otto, plus his friend Juliet and her cat Cornelius, join Max on a strange and dangerous journey to rescue Otto's mother - in a world where anything is possible...