Peter Laxter's will provides a life time job for Charles Aston, his faithful caretaker. When the Laxter heirs threaten to poison his cat, Ashton seeks Perry Mason's help. Perry, suspicious of the Laxter will, decides to use Clinker to break it. Ashton is found murdered and his sheets covered with tracks. A cat accused of murder? Well, no! But Clinker does play a star role in the dramatic courtroom finish. With the help of the caretaker's cat, Perry Mason scores a daring last-minute victory, exposes a shyster lawyer, and brings a murderer to justice.