How does the grandmother talk Bailey into going to the plantation?

When the Grandmother remembers an old plantation that she thinks used to be in the area they are traveling, Bailey does not want to take a detour to go find it. As a result, the Grandmother makes up a lie about how there are secret doors in the house with hidden treasure, causing June Star and John Wesley scream and complain until their father agrees turn around and drive down the dirt driveway.