Meredith Hortweldine secures the services of Jeff and Jeannie because he suspects his twin brother Jasper is plotting to kill him. Jasper has the same notion about Meredith and employs a rival detective duo called Marshall and Snellgrove. A bomb explodes, killing Meredith and Snellgrove, the latter's ghost teaming up with Marty to unmask the murderer. Marty also discovers that he was claimed before his time and that another Martin Hopkirk should have died in his stead.