A dream holiday in a 17th century Irish castle turns into a nightmare for very modern thirteen year old cousins Bridgit and Rory O'Sullivan. Things disappear and when Bridgit's dog gets sick poison is suspected! Meanwhile, the adults in the castle are plotting against them...and against each other. Or are they? Bridgit and Rory have just three weeks to find the answers. Kids through middle school will enjoy the excitement and mystery of a summer holiday at O'Sulivan's Hill!