The phrase "basic plot" refers to the main storyline or outline of a story or movie. It is the foundation or structure upon which the details and events of the narrative are built. Full definition
The top 50 YA books share dozens of identical elements and the same basic plot lines and characters. (creativindie.com)
Using newer voice actors, most of whom are spot on, this version has some of the same basic plot points as the original. (rottentomatoes.com)
The weekly sessions include in - depth character profiles, basic plot structure / beat sheets, where to start your novel, and the challenges of writing the middle of your novel. (desmoineswritersworkshop.com)