Adapted from A. J. Cronin's play, a gruff doctor experiments on a drug for mental patients and gets help from a devoted assistant.
In 1935 Budapest Dr. Paul Venner (James Stephenson) waits to see Professor Von Reiter (Sig Ruman) while Esterhazy goes in and says that Venner claimed Von Reiter stole his research. Von Reiter apologizes to Venner and promises to correct it; but he makes a call, and Venner is deported by the police without his records.
In London Dr. Venner learns his money is still being held. Dr. Drewett (Donald Crisp) tells Paul Venner he is working in a sanitarium in Scotland. Dr. Blake (Montagu Love) offers Paul a laboratory and patients for experimentation. Paul criticizes Dr. Thornton (George P. Huntley) and is served by Miss Leeming (Barbara O'Neil). Blake assigns Dr. Mary Murray (Geraldine Fitzgerald) to assist Paul; but he objects she is not trained. Blake proposes one month probation. Mary breaks a bottle, and Paul gets angry. Drewett says Paul's lab needs cleaning, and Mary wants to order it but is afraid. Drewett explains Paul has had a hard time and hopes to cure dementia. Mary says she is going to be a missionary in China. Miss Leeming asks Paul about her sister, and he is short with her. He finds his lab is clean and neat. Drewett tells Thornton to ask Paul for help treating Nancy. Mary finds that Paul's patients are better. Paul has trouble with Foster (Leonard Mudie), but Mary is able to give him an injection. Blake asks to use Paul's injection on Nancy, but Paul says no. Mary works overtime with Paul. Jealous Miss Leeming warns Mary that Paul is cruel and advises her to leave. Paul tells Blake he can't release his formula until he examines the brain of a dead patient.
Mary gets Paul to sleep and does the work. Paul thanks her and apologizes. Mrs. Foster tells Paul she hopes her husband can return to work. Paul tells Mary that Foster has a bad heart, and he is eager for his death. Mary understands why Foster fears Paul. Chivers offers Paul a position with a drug company for his solution, but Paul says no. Miss Leeming tells Paul that Mary is leaving soon. Paul asks Mary to stay and if she wants to marry him. Paul buys her two rings, and they go on a picnic. Paul learns that Foster died and examines his brain without getting permission. Blake complains. Miss Leeming threatens to tell Mrs. Foster if Paul marries Mary. Paul says that she is sick with jealousy. Miss Leeming starts a fire in the lab. Mary goes in and throws Paul's record book out the window but dies. Blake and Thornton say that Paul is a great success. Paul tells Drewett he is going to China because of an epidemic. In the rain Paul remembers his picnic with Mary.
This drama shows two altruistic personalities drawn
together in their mutual dedication to help humanity, enabling
them to transcend minor irritations and find a deep love for each
other as well.