On the one hand the law doesn't want to protect only the exact words of a work, allowing a plagiarist to get away with copying by making minor changes. On the other hand, it doesn't want to protect broad themes or plots or generic characters because to do so would limit the ability of future authors to create their works. Judges have to decide close calls on a case by case basis. Generally, the more specific or original the creation, the better the chance that it will get copyright protection. Ownership Usually the creator of the work owns the copyright.
Courts use several factors to determine whether a given work is a work for hire.
See CCNV v. Reid . Occasionally, more than one person will contribute to the creation of a work. Only the holder of a copyright can make a DW based on the copyrighted work. This is what allows movie rental stores to exist. Exception to 1st sale doctrine for sound recordings 4.