What is the importance of "Clock Island" in the novel, The Wishing Game?

Clock Island is a fictional location that Jack Masterson has created. It is off the shore of Maine. On the island, each number on a clock represents a place. The Mastermind lives on the island in the Clock Island books. Jack creates a real island base off of this, and this is where the contest takes place that Lucy participates in. This is also where Lucy and numerous other children run away to in order to find the Mastermind. By the end of the novel, Christopher and Lucy have moved to the island.