WHO PRAY TOGETHER SLAY TOGETHER
Psychiatrist, Gregor Maclean, investigates a patient’s suicide and lands in a curious sect which he suspects of brainwashing its members into committing suicide to seize their possessions. He and his helpmeet, Deirdre, join the sect but she falls victim to their brainwashing and tries to kill Maclean. Even after resolving the murder mystery, he has the problem of redeeming Deirdre’s sanity.
Into Maclean’s consulting room comes a girl who threatens to commit suicide. She is convinced she will be murdered unless she finds protection and somewhere to hide. She says someone called The Founder will also be murdered. Maclean and his secretary Deirdre discover her case is full of banknotes and jewelry.
She disappears then calls and asks him to bring her money to a rendezvous. He narrowly escapes being run down and killed by the persons collecting the money.
Several days later, the girl is found dead in a hotel room. Although it seems suicide, Maclean is suspicious. He traces the money to a bank account and discovers this belongs to a sect called the Transastrians. He recalls treating a sect member who also committed suicide.
He manages to penetrate the sect, discovering it brainwashes its members with pseudo-science, hypnosis, drugs and religion; but its aim is really to acquire their money and property. Marcia Bennett, the dead girl, had handed over her large inheritance.
Maclean persuades Deirdre to join the sect and becomes a member himself to find out how and why the girl died. The sect leaders try to brainwash him.
By burgling the office and spying on the leaders, he discovers Marcia Bennett was running away with the sect founder, Julian Crayne, who had fallen in love with her and knew she was having his child. He has the idea that Crayne, too, was murdered but is puzzled when he sees him in the flesh. Maclean also finds out how the sect makes it money; Granton, their medical guru, plants post-hypnotic suggestions of suicide in the minds of the members then collects their inheritance when they kill themselves.
Deirdre is brainwashed and now treats Maclean as a stranger and an enemy. Under hypnosis, Granton has her reveal everything then orders her to kill him.
Maclean finds the Founder is dead, replaced by an impostor with the connivance of his widow. In trying to trace the body he is taken prisoner.
They confront him with Deirdre, determined to shoot him. When he fights back, she accidentally kills Granton and he masters the other two conspirators.
Deirdre is still a problem, for she is under the influence of a post-hypnotic suggestion planted by the dead Grafton, which only he can cancel. Maclean finds someone to trick Deirdre by mimicking Grafton’s voice, lift the post-hypnotic suggestion and erase everything about Transastrianism from Deirdre’s mind.