Proscenophobia (Stage Fright)

The star - Addie - is attempting a comeback and is understudied by her best friend Millie

Their constant bickering belies a long history of friendship, which includes each of them having been married to the same charming impresario, Ed Gibb

Suspense builds when Addie begins to feel unwell and, for the first time, Mille must take her place

But then during the final act of the play, the violence becomes real and Millie is found dead

With everyone suspect, the tension doesn't let up until the final revelation