Dr Belasco is Scotland Yard's top target and the Temples go incognito to meet Belasco's right-hand man Ross Hunter on the Harwich boat train but circumstances overtake them and Temple is faced with the murder of a private detective, cigarette lighters with a distinctive acorn motif and more murders before Belasco is finally unmasked. Francis Durbridge is one of the finest manufacturers of red herrings in the whodunnit business.