The festive season has come to Sinclair's and Sophie and Lil are spending the holidays at snowy Winter Hall. But it turns out that this is no ordinary house party ...As sinister secrets come to light, our intrepid heroines find themselves faced with a more baffling mystery than ever before! With the help of their friends, can they uncover the truth in time to foil a truly diabolical plot? Or will Mr Sinclair's New Year's Eve Midnight Peacock Ball spell disaster for the dauntless young detectives? Prepare for shocks and surprises in the thrilling conclusion to the Sinclair's Mysteries!