Where did you get the idea for your most recent book?

I got the idea back in high school while taking a creative writing course.
Our assignment was to write a short story and at first I didn’t know where to start.
In class I wrote down a bunch of random scenarios, feeling frustrated with myself for not coming up with anything that piqued my interested, and then one night while I was sleeping I had a very vivid dream about a girl named Rose, her uncle and a boy named Nicholas. This dream ended up being the first chapter in book one and went from being used as short story to a novel series.