Miss Lucy Pym a popular English psychologist is guest lecturer at a physical training college. The year s term is nearly over and Miss Pym -- inquisitive and observant -- detects a furtiveness in the behavior of one student during a final exam. She prevents the girl from cheating by destroying her crib notes. But Miss Pym s cover-up of one crime precipitates another -- a fatal accident that only her psychological theories can prove was really murder.