Hagbane's Doom: The Oswain Tales, Book 1 (Unabridged‪)‬

Three children, Sophie, Josh, and Andrew find something very mysterious about an archway in their local park: It seems to have their own names inscribed on it. Going through the archway, they find themselves transported into another world, caught up in a battle to save the Forest of Alamore from the wicked crone Hagbane, who has stolen the Merestone - a magical stone that is essential to keep the forest alive.

Prince Oswain, the children, and the forest must face Hagbane and her army of Grims and Grogs, to restore the Merestone to its rightful place.