A while ago I read this book as a free Kindle book, but forgot the name of it, and now I can’t find it. It’s not on my Kindle or Amazon either.
The book begins with a teenage girl sneaking into a space ship that’s headed out for another planet (might be Earth) but it crashes.
The team leaves her behind, and then she finds someone (a boy) who is very quick and strong and knocks her out and takes her through a portal, if I remember correctly.
I think he takes her to his mother's house where she gets treated, and the guy's brother is a king or something of this sort, and he leads the army that defends their kingdom from monsters.
They have a "will they won’t they" relationship (enemies to lovers). But at the end of the book the girl gets a message that someone has her brother and she gets the guy to escort her out and then the book ends.