After a late night break-in at the British Museum, nine-year-old investigator Lottie and her friends discover a clue on the Rosetta Stone that may lead them to the legendary Trident of Neptune.

In 1928, nine-year-old investigator Lottie and her friends try to save the British Museum from shuttering its doors by looking for a buried treasure in a secret tunnel beneath the museum, only to discover they must solve a series of puzzles to find the treasure as well as their way out of the maze of passageways.

In 1928, nine-year-old investigator Lottie, in an effort to be helpful, incorrectly deciphers a spell that allows Egyptian statues to run rampant around the British Museum.