Maryellen takes a break from practicing for the big "Rock Around the Clock" holiday dance to go to the beach with her friend Davy. While playing in the waves, they find a barnacle-encrusted ring buried in the sand. They imagine that it's lost treasure from a sunken ship. But why do other people seem desperate to get the ring?

Scooter, Maryellen's pudgy pet dachshund, may be lazy, but he's one of the family, and Maryellen loves him dearly. And he never misses a meal! So when Scooter doesn't show up at dinnertime, she's worried. Maryellen launches a search—and discovers some strange goings-on in her neighborhood. With the help of her friends and family, the search for Scooter takes Maryellen from the streets of Daytona Beach to the rocket launchpad at Cape Canaveral!