Complete the analogy: Chapter : Book :: Scene : ?

A chapter is one of the named parts into which a book is divided, so the second word is the whole that the first word is a piece of. A scene is one of the named parts into which a play is divided, so the missing word is Play. The traps: an actor performs in a play but is not made of scenes, and a stage and a curtain are pieces of equipment used for a play, not divisions of it.