Which element of a novel is an idea or message that runs through the entire story?

setting
characters
plot
theme

Theme.

Explanation:

The theme is the central element of the story that lingers around the entire course of the story. In fact, it is the theme that drives the plot, setting, and characters of the story. It is the central idea of the story that assists to convey the intended lesson or message to the audience and also the point of view of the author. It acts as a link to connect the different elements like plot, setting, characters, events, conflicts of the story. It shapes the story and provides a direction to it and aids to develop and carry forward the story. Thus, it is the theme that runs throughout the story and determines the action and events of the story.

of course not love is   love u cant change it.