Maths-whizz Alice has already solved a mystery or two. Persuaded
by wannabe sidekick Sammy to investigate a scientist's disappearance,
she's soon entangled in her trickiest case yet. Dr Learner is
reputed to have invented an invisibility suit, but is whacky science
really to blame for his vanishing?
With the unlikely help of erstwhile nemesis Kevin, Alice solves the
puzzle - only to face another. Should she reveal the truth, or
protect her most devoted friend?