When two editors open the same draft line, they are editing one document. Each sees the other's cursor and selection, labeled with their name, and every keystroke arrives as it is typed. Nothing has to be merged afterwards; the script is simply shared.
Presence
The header shows who else has the document open. Select a name to jump to where they are working.
Following someone
Ghost Mode follows a collaborator's cursor: the page scrolls with them and their selection is yours to watch, without you touching the text. It is the way to read a rewrite as it happens, or to walk a co-writer through a scene on a call. Leave it by moving your own cursor.
Holding a scene
If you want a scene to yourself for a while, hold it from the outline. Others see the hold with your name on it and are asked before they edit inside it; it is a courtesy, not a lock, and it lifts when you release it or leave.
Going offline
Lose the connection and you keep writing; the editor stores your changes and sends them when you are back. If the same passage was changed by both of you in the meantime, Plot shows both versions and asks which to keep rather than choosing for you.
Working apart on purpose
For a rewrite you do not want to share keystroke by keystroke, work on your own draft line and incorporate it when it is ready — see Draft lines.