When their father accepts a new job in England, July, Liberty, and their family find themselves exploring the foggy streets of London. The twins try to discover the source of the voice only they can hear—a voice that needs their help. Using telepathy and their individual talents, the twins uncover a long-lost manuscript of Sir Arthur Conan Doyle’s, along with the ghost of Sherlock Holmes’s forgotten twin brother.

When the Starbuck family moves to a houseboat in the Florida Keys, the children love their new home and soon discover they share a wonderful telepathic link with the dolphins. When they find that someone is poisoning the water with toxic waste and that the creatures of the Keys are dying, the twins must stop the culprits before it’s too late.

The telepathic twins and their family journey to the American Southwest where they discover some ancient Anasazi pottery shards and embark on an exciting adventure filled with danger, mystery, and a ghost.