“A comedy based upon conflicts between Irish and Jews, into which the marriage of their children enters, is no more susceptible of copyright than the outline of Romeo and Juliet.”
L. Hand, Circuit Judge., Nichols v. Universal Pictures Corporation, 45 F.2d 119 (2d Cir. 1930).
Even though copyright law only requires a modicum of creativity for a work to be copyrightable, too general a storyline is not copyrightable. Similarly, common type characters are not copyrightable. (For example, one eye-patched pirate with a talking pet parrot or a mean monstrous mother-in-law, etc.) There must be some distinctive character and plot details. After-all, the purpose of copyright law is to promote arts and science. Writers will have stronger copyright in their work when the plot is more unexpectable and characters are more developed, as it would be too obvious when one copies a story so unique and characters so fully developed.
Law in Style. 