"Duet for Dying" is a very poor episode of "Barnaby Jones". I think it was intended to be funny, but bad acting by the guest stars really made this one a tough sell for me.
The story begins with a lady cavorting in a pool with an older man. You can understand why the younger lady is interested in him when it turns out her sister is in the man's apartment ransacking the place for some valuable coin collection. Unfortunately, he returns to the room to early and the sister is caught. A fight ensues and the ladies kill him...and take his coins as well.
It turns out these sisters have one goal in life....to be famous professional singers. They kill and steal and feel no sense of guilt...and later, they kill again...all to further their ambitions.
Throughout the episode, you hear man after man say how beautiful these ladies were. Well, I know this won't sound very nice, but if you want to describe them this way, make sure they actually ARE good looking and not the two most annoying characters I can ever recall on the show. Now had the men described them as bad actresses playing annoying characters, that I could have agreed with...wholeheartedly. Two very dumb ladies and a couple very dumb guys...an episode should not rely so heavily on folks being dumber than tomatoes.
By the way, I find it hard to believe but these same two sisters would appear in another episode during season 5! Apparently SOMEONE from the show thought these dopey sisters were great characters.