spoiler-free thoughts about ninth house and its trilogy

I’m currently reading a friend’s copy of Ninth House and I’m a hundred pages in, and so far I’m quite intrigued with the story’s direction.

However, I just realized that this book was a trilogy, and I wanted to know your spoiler-free thoughts regarding this book and its succeeding stories, since I’ll be busy the next coming months and just wanted to gauge whether continuing on with the series will be worth it or not.