Back when I read this I didn't realize it's a direct sequel to "Simon vs the Homo Sapiens Agenda" rather than just existing in the same universe, and I guess mixing up the order really did spoiler me a lot. So, yup, don't do that - read Simon first, then this.

And yup, the tension between Leah and Abby goes way back and really needed to be addressed with its own backstory and future, they deserve it. However, once again, why the wizard school references everywhere??? Really ruins it.