If you have a difficult time writing loglines here are two logline templates I’ve slightly altered from Max Adams’ book The Screenwriter’s Survival Guide.
The first is for stories where the protagonist’s problem is an external force like a monster or evil men. The second is when a protagonist’s problem is an internal bad guy, like a poor attitude toward love or growing older.
1. (Title) is a (genre) about (protagonist) who must (tangible goal) or else (dire thing that will occur if protagonist fails — Ex: who must find the lost Ark of the Covenant and keep it safe or else the Nazis will use it to rule the world; Indiana Jones and the Raiders of the Lost Ark).
2. (Title) is a (genre) about (protagonist) who (inciting incident that creates the problematic circumstances, preferably ironic — Ex: who falls in love with her fiance’s brother; Moonstruck).