Sir Wilfrid Robarts is an ailing barrister who has been told that he should accept fewer legal cases for the sake of his health. However, he cannot resist defending Leonard Stephen Vole, a man accused of murder whose only alibi is provided by his devoted wife, Christine. The police are convinced of Vole's guilt as he stands to benefit financially from the murder, but Robarts believes that he can prove the man's innocence in court.