Isaac Severy, venerable patriarch of the brainy and eccentric Severy clan, has just died and the bereft family members are struggling to cope. His granddaughter Hazel receives a posthumous note from Isaac, who was a famous mathematician, setting her off on a search for an equation. Given only a few mysterious clues, she is asked to find the equation and deliver it to Isaac's friend for safe keeping. During the search she discovers that there are lots of secrets spread throughout the family.
This is an inventive mystery with surprising plot twists, and I liked it very much. However I do feel it is a bit too ambitious in some respects. There are so many characters that I had to stop and create a family tree on paper to keep all the relatives straight. Many of them appear multiple times and take up space, but are not part of the main plot. One or two sub-plots could be dispensed with, too. I just think it needed some editing, to give the main characters some breathing space and develop them more. I wanted to know Hazel better, as she seemed quite interesting.
This is an impressive debut novel and I really did enjoy it, so I feel bad criticizing it. It just took a lot for me to work through it. I'll be watching for Jacobs' next book, to see what sort of interesting new story she constructs!