A diamond that can turn people in to chalk; a talking computer and an eccentric chess master called Ceribraun involve Tarot in a new and interesting mystery.

Ceribraun's trap for Tarot is well baited - with Mr. Sweet! But when it appears that the Eye of Ra has turned Mr. Sweet into a tiny chalk statue, Tarot, Lulli and Sam decide to act

Using telepathy, Lulli communicates to Tarot that she is a prisoner in Sir John Peckham's vaults and that she has been turned into a 6-inch high chalk statue. Tarot races to her rescue, but someone else is waiting for him.