A bike ride at the beginning of the summer break turns into a fantastic, sometimes terrifying, weird and wonderful adventure for twelve-year-olds: Samantha (Sam) Craig, Ben Cooper, and Tommy (Frog) Scott.
Finding a chalice made of gold behind a waterfall, the three pals are transported to a different dimension, into a world where all manner of surprises and dangers lurk at every turn.
Like it or not, the trio have been chosen to return the long lost chalice to the Keeper-in-Waiting, and only by fulfilling the mission will they have any chance of returning to their own world.
The Chalice of Hope is the embodiment of all that is good, and must not be allowed to fall into the hands of the Dark One, for fear of evil spreading unchecked throughout Allworlds.
Accompanied by two fairies, Figwort and Speedwell, (Fig and Speedy), Sam, Ben and Tommy set off on what proves to be a perilous journey through many lands, and are joined by Gorffin, (Gorf), a giant hairy troll from the Desert of Storms.
Now numbering six, they venture into the unknown, having to face constant dangers and overcome many ferocious creatures and strange beings.