From Archive of American Television

Was that your first time directing?

Leonard Nimoy: First time directing for television, yes. The producer again was a guy who had a track record for starting directors and I was given a very lovely script which was called Death on a Barge which was a Romeo and Juliet story in Vampire terms.

The girl is a Vampire, we discover. And dangerous. And her father knows that she is a Vampire and keeps her on a barge because the barge is surrounded by flowing water and a drainage canal. And a Vampire cannot cross flowing water.
So he feels he’s got her safely locked up on this barge. A young guy comes down in the dark and sees her. He is on the dock, she is on the barge, and they fall in love with each other through conversation. And eventually one day the young guy comes to talk to her and discovers that the canal has been drained. The water is gone. And she is out somewhere. She is out and will kill somebody.

But he is still very much attracted to her and ends up going on board the barge to have a private moment which turns to disaster.