I have a question: our theater group is contemplating a classic play for which we
cannot find a decent script (the story is in the public domain). We'd like
to write our own, but we like certain elements in one of the available
scripts. How many ideas can we use without it being considered plagiarizing?

The ideas are actually sort of old: beginning the scenes with the actors
frozen in place, using sepia-toned lighting to make the frozen scene look
like an old photograph, having a narrator to fill the audience in on certain
things. The order of events would be different, we would create more and
different characters and we wouldn't refer to the existing script when writing the new one.

Any thoughts?

Thanks,

Susan