The Standing Stones

From publisher blurb:

A tomb. A story. A puzzle. An ability score boost. And TREASURE! Standing Stones is a mini adventure that can fit into any forest setting. It can be used as players pass through and want treasure, or during an ongoing local campaign where players can return to get ability score bonuses as needed. The choice is yours.

Pick up Standing Stones if your characters need a little boost and you want to wrap the boon up in fancy story wrapping paper. There are six stones, and each one gives a temporary ability score bonus. In addition, the stones hold a mystery that, when solved, opens up the tomb — and the treasure!