The Saint is invited by George Hapgood, a designer of racing cars ,to test drive his latest model, but the car has been sabotaged and crashes. George's cousin Justin then asks the Saint to drive his latest car only for a mystery driver to force that car off the road as well. The Saint suspects business-woman Kay Collingwood as being involved given that she seems close to Justin but she claims that her main interest is in bugging devices, not cars. The Saint gets ready to drive George's car in a rally, unaware that it has once more been sabotaged.