In a city overcome by fear, a young scientist whose sister stands accused of witchcraft must prove witches aren't real by untangling local corruption and conspiracy in this young adult historical fantasy mystery perfect for fans of A Tempest of Tea and Chloe Gong.

In late 1800s Switzerland, Geneva is at the center of a new and exciting age of innovation. Yet the recent breakthroughs in electricity fail to outshine the growing fear and unrest among the people. A mysterious disease is plaguing the city. Worse: sea monsters have been seen in the lake?snapping the cables of newfangled trolleys and terrifying the populace. There can only be one explanation...witches.

Now with someone to blame, people are quick to take their anger out on nonconformist young women they accuse of being involved in the dark arts. When the mania reaches the home of seventeen-year-old Mimì Bouchon, a young pharmacist, her younger sister, Léa, is charged with witchcraft, dragged from the house, and imprisoned. A trial is set?and no one is ever found innocent. With only a week until Léa's court date, Mimì desperately looks for a way to save her from a brutal sentence, but not a single reputable lawyer is willing to take the case. Then Mimì finds herself accused of witchcraft.

But luck, for once, is on her side. A young man named John comes to her aid, and he is not only a lawyer but also a scientist. He certainly does not believe in witches. John agrees to take Léa's case and plans to defend her by proving in court?using science, including Mimì's knowledge of chemistry?that witches do not exist. While their shared mission brings Mimì and John closer, it also draws attention from the city's elites, who will do anything to stop the pair from digging for the truth behind the hysteria.

Can Mimì and John's logic and conviction stand against the fearmongering of those in power?