When Professor Giles Dawson, historian of magic and the great illusionists, visits the Circus Tropicana, wintering at a former RAF airfield in Devon, he is not there to be entertained. He is there at the request of the circus boss, Ramon Mordomo. Ramon Mordomo has experienced a series of disasters at the circus, which appear to be the work of someone trying to force him to give up the circus he loves - making him run the Gauntlet of Fear. Once Giles has been introduced to the list of suspects, he witnesses a number of so-called accidents - which any one of the suspects could have caused. He then receives some cryptic messages.... which only add more mystery to the puzzle. Things turn deadly when an accident in the ring turns out to be murder... watched by hundreds of spectators. The attempt to solve the riddle leads Giles to York, where the circus opens the season and where a second murder is committed in a locked room. A murder which is so bizarre that supernatural influences might have to be considered. As Giles begins to solve the riddle, he realises he can't prove his suspicions. So he calls together all the suspects and plays a magic trick .... a trick designed to lure the culprit into a deadly confrontation.