Summer is not looking good for Duncan. His parents have left him with his Great Aunt Harriet at Arthritis Hall, a retirement community of rude old ladies who confiscate his games, stuff him in a windowless room and just want him to keep quiet.

When Duncan meets Ursula, the caretaker's daughter, he begins to discover the diabolical secrets that lurk in the shadows of Arthritis Hall. Soon, the two children find themselves embroiled in a plot involving bizarre electronic creatures and acts of ingenious thievery, in an attempt to outwit a fiendish group of eldery criminal masterminds.