A phone call arrives in the office of Mr Keen. It’s a man who is in immediate need of help, but before he can finish the call, he drops dead. On the crime scene, Mr Keen finds a young woman lurking. She seems awfully defensive, but did she poison Stewart Blair?
Clues send our heros on the trail of Lenore Barklay, a secretary at a law firm. The lurking girl, Miss Holm, is discovered to be Blairs fiancee, might there be some rivalry between Lenore and Miss Holm? Mr Keen believes it’s important to know the poison that killed Stewart, but the reports from the lab aren’t in yet. Lenore is interviewed, and when she swoons, Mr Keen figures it’s poison. Who would want her dead as well? Might Lenore’s boss, Mr Carter have anything to do with the crime? He turned down the victim for a job in the past.
Mr Keen meets Lenore’s mom, more facts emerge, the cops phone Mr Keen with the word on the poison, and he is beginning to figure out who the killer is. It’s just a matter of getting the solid evidence he needs. The players are all gathered together, and Mr Keen lays all his cards on the table. The killer doesn’t stand a chance when Mr Keen puts the finger on them.