Mary Wesley is an old school friend of Valerie Johnson, famed circus trapeze artist, so Mary and Blackie go to the circus to see the flying Johnson family perform. Just before the act Valerie gives Mary a note warning her that if she is killed during the performance it will not be an accident but murder. Valerie is killed and in an investigation before the arrival of Inspector Faraday, Blackie uncovers three suspects; Harry, the dead girls husband and partner, Joe Laine and Smithfield the circus ringmaster whom Blackie caught hiding in Laine's dressing room.