A ferocious storm has caused flotsam to wash up on the shores of Schooner Cove. Among the seaweed and kelp, driftwood and other jetsam Cecilia, Leo and Une also find a dead serpent, unusually large in size. Their find attracts a lot of attention, especially from the press who call it a “sea serpent”.

At the same time, one of the guests at The Pearl falls ill. The doctors say that she has been poisoned. Just as they are about to load her into an ambulance, the woman whispers something. It sounds like the word Phoneutria. Cecilia, Leo and Une discover that Phoneutria is the Latin name of one of the most venomous species of spider there is, but little do they know that the deadly arachnid is still hiding somewhere in The Pearl.

The CLUE series’ name comes from the first letter in each protagonist’s name: Cecilia, Leo, Une, and Une’s dog Egon. In each of the series’ books a new mystery and a new ethical question is introduced along with the thoughts of one of the world’s most well-known philosophers. The CLUE books are best selling crime fiction for younger readers aged 9-12.