Jem is turning eight years old. And there's just one thing he wants for his birthday: a prospecting trip with Strike-it-rich Sam. With his grown-up friend to watch out for him, Jem's parents say yes. It's off for two weeks in the mountains to find gold! But this trip isn't going as planned. There are more tall tales from Sam than there are deep pockets of gold ore. And the map to rich diggings they brought along doesn't have any treasure at the end of it. Striking it rich is a lot harder than it looks.

When they find an unexpected cache, things seem to be looking up. But Jem and Sam shouldn't count their gold nuggets before they get home. An injury, a bad detour, and other problems plague them. Not only are they empty-handed, they might never make it home at all!