Harry Plotter

Sis Lettie will not let him go

She mettles and plots don't you know 

She'll keep and enjoy him

Or bleeping destroy him
She's getting the hots for her bro. 

Geraldine Fitzgerald gives a chilling performance as Lettie, controlling sister of Harry (George Sanders) in The Strange Affair of Uncle Harry (Robert Siodmak; 1945). 

The Trouble With Uncle Harry

Consider the strings on this mope
From a sister who clings to a hope
She's a brat and he blames her
For fratricide frames her
And insists that she swings from a rope.

In The Strange Affair of Uncle Harry (Robert Siodmak; 1945), George Sanders feels trapped by his sister Geraldine Fitzgerald.

Say Uncle

The sister, conniving and cruel
The miss, so alive and so cool
At stake is the brother
One will make him, one smother 

There's a twist: who survives this film duel?

Geraldine Fitzgerald and Ella Raines in The Strange Affair of Uncle Harry (Robert Siodmak; 1945).