The simple, yet effective set and lighting/sound design added to the story.
What I didn't like
It all worked.
My overall impression
First of all, I love a good thriller! On The Line delivered on all levels. A solid nod to Sorry, Wrong Number, When A Stranger Calls and Dial M For Murder. I was on the edge of my seat trying to figure out who the “bad” person was. Great writing and directing by Pamela Eberhardt and Dan Testa.