From The Perry Mason TV Show Book (Revised)
Check out the lineup of women in this opening scene. It looks like a 1950s Hollywood casting call. Eva Martell gets a part, not on stage but impersonating Helen Reynolds, a woman she has never met. She is paid extremely well and given a beautiful apartment to live in with her Aunt Agnes as long as she continues the charade. Still, Eva suspects foul play in paradise, and seeks the advice of a good lawyer.

Perry steps in and meets with the real Helen Reynolds, who swears she is not doing anything illegal, but cannot reveal her motives. That’s fine until they find that dead body in her apartment…