I haven’t read the first book in the series but I don’t feel like missing anything major as the characters are well depicted and the story it’s not following any major twists apparently.
She seems to be Dexter female clone and the author has done a great job in showing how a psychopath can live their lives with no worries and emotions for anyone but the chosen ones as in this case her boyfriend, who was a bit obvious to everything around him in my opinion ( that’s a very nice way of describing him