A film treatment (or simply treatment) is a piece of prose, typically the step between scene cards (index cards) and the first draft of a screenplay for a motion picture, television program, or radio play. It is generally longer and more detailed than an outline (or one-page synopsis), and it may include details of directorial style that an outline omits. Treatments read like a short story, but are told in the present tense and describe events as they happen. A treatment may also be created in the process of adapting a novel, play, or other pre-existing work into a screenplay.
Learn a little on how treatments are formed by these two videos below. Enjoy!
How to make a director's treatment by Mathew Dawson
How to write a treatment by Danny Feng