It is a mystery but it is a ride-along one. You aren’t going to solve this until the author wants you to. It reminds me of a more reader-friendly Morning Glories.
Speaking of which the book is drawn by Morning Glories cover artist Rodin Esquejo meaning the art is breath-taking. It is digital and benefits from some sophisticated effects but it keeps that pastel feel and wonderful tangibility. You can see so much effort goes into each panel and the framing and composition are always daring and innovative.
The book hits the ground running and sweeps you along as it sets up its detailed characters and their uncertain relationships. Because there is so much dialogue it does slow down but you really want to find out who did it. There is a satisfying ending to part one that makes you want more. Despite being only five issues this is lengthy and meaty read.