Summer vacation is approaching, and the deBoer siblings, Daniel, Maria, and Elise, want to have an exciting adventure. Visiting Oupa and Ouma on Willowdell farm in central Pennsylvania is not what they have in mind! Oupa and Ouma need help and ask for an extended visit. The farm vacation takes many unexpected and exciting turns. Oupa shares his stories and delights the siblings. Under the happy surface lurks a serious problem. Daniel discovers that intruders visit the farm at night in search of a treasure. Who are they, and for what are they looking? The entire family soon find themselves in a race to find the valuable treasure and to keep it from falling into the wrong hands. Oupa delightfully draws on everyone’s strengths and eccentricities. Will they win with whit and cunning? The vacation turns into just the fast-paced adventure Daniel wanted, and it far exceeds his wildest expectations!