Sam and Beth accompany their mother on a visit to their grandfather's home on Oak Island. This is their first visit in three years, since their mother and grand-dad had a terrible fight over something nobody wants to talk about. What occurs when they arrive is more than Sam could have hoped for, more surprising than the magic tricks he spends hours perfecting. Something strange seems to be happening to grand-dad, a fact confirmed by his odd behavior and the disgusting state of his once-immaculate home. Apart from losing his memory, he's also spending a lot of time engaged in a bizarre hunt for a 200-year-old treasure. When Sam is bitten by the treasure bug too, not even the discovery of a human skull or a dangerous run-in with a monstrous digging machine can keep him and the whole family from plunging into a breakneck-speed mystery, in which the winner will take all.