The fourth and final book in the Magicae Mathematica series concludes the story of Alex, Archimedes, and many other beloved characters as they fight against the evil Master Wizards who possess a device that could destroy the world. With time and hope running out, can Alex become the missing variable that everyone believes she is?

With recent losses from both sides heavy and heartbreaking, and the most difficult decisions yet to be made. Will the Guardians make it through the mountains? Will Councilman Semlac and the people of the city make it to the Black Castle? Will Alex find her true power? Will the wizards destroy the world?

Decisions, consequences, losses, risks, and sacrifices awaits Alex and her friends.