The Aldens are helping the owner of a local restaurant grow delicious food in a garden. They work hard to water and weed and take care of the fruits and vegetables that are growing. But soon the children notice the strangest thing—the plants are moving. The tomato plants aren't in the same spot they were planted in! How could that be happening? Then, when fruits and vegetables start to vanish from the garden, it's clear that a brand new mystery is sprouting for the Boxcar Children.