The Wizard's Heir — Andrea Eames

The blank wall in front of them seemed to dissolve, and a creature Peter had never seen before bounced through. It looked like a large rodent, but with six arms and one long leg shaped like a spring that ended in an enormous foot. ‘A Haha!' exclaimed Duncan. ‘I wonder,' began Cat pompously, ‘if you could tell us…' ‘Help!' squeaked the Haha, its expression distraught. ‘The Caretaker's gone missing!' Duncan and Emma return to the Lost Land with a new friend, Peter, only to find that the Caretaker has vanished and the Land is in danger from a new and mysterious darkness. Can they save the magical world a second time? And will Peter be able to overcome his fears and play his part?