A suspicious personal ad conceals nefarious intent--and eventually lands in the lap of Perry Mason. It appears that Marilyn Marlow inherited a small fortune from her mother, who got the sum from her wealthy employer. But now the old man's relatives are contesting the will. Whoever sways Rose Keeling, the key witness to the signing of the will, is sure to be the victor. Enter the personal ad. Marilyn intends to find Rose a Mr. Right--in order to get the goods on her. But when Rose is murdered, Perry Mason sets out to find a gentleman caller who had a date with death.