In French cemeteries, "perpetuité" only lasts for a hundred years. If the deceased's family wants to keep their dead buried, they must pay the rent.
If not, the municipality will excavate the tomb to liberate the space for a new family.
After the latest excavation, Robert and Clothilde find themselves faced with a ghost much older than themselves - along with the daunting task of solving a century-old mystery.
Is it still possible to find eternal rest for their new friend?