After the cunning and complicated Elizabeth Zisk is removed as mayor of the town of Question Mark by the Town Council, Violet immediately asks Ms. Twombley, the head librarian for help. Ms. Twombley uncovers some information regarding Appendix Nine of the town charter, which can reinstate a mayor once they have been removed. However Appendix Nine has been locked in the town vault for the last one-hundred-seventy years and the only way to open the town vault is to locate the missing town key.

Violet receives a plea from former Mayor Zisk, who has taken a job at Holy Romaine Empire, and who reveals Thompson Zisk, her long dead husband and a former mayor, was in fear of being removed and had also been searching for the missing town key. He believed a pair of mayoral cufflinks–passed down from mayor to mayor–may have included an important code, but after the fire that claimed his life and led to the ruin of the Cell-Con cell phone factory, Thompson Zisk was buried with these important cufflinks.

Asking Officer Ron for help, the two travel to St. Casimir’s Non-Denominational Cemetery and retrieve the cufflinks. Iris helps decode the message, which leads Violet and Iris to the Question Mark Falls the following day. There, behind a curtain of ice-cold water, they find another message inscribed directly into the cliff face, warning them about the danger of individuals who want to wield the power of the few over the power of the many and suggesting that the town key may have been stolen by former industrialist, Lawrence Ames.

Meanwhile, Officer Ron receives a coded message of his own inside a file folder of newspaper clippings, outlining several corruption cases within the police department. There is also a clipping detailing his father’s accidental death while on duty. Decoding the message, Ron finds someone is trying to warn him about a much larger criminal plot involving the QMPD and possibly the death of his father.

With helpful information from Holly Peterson, Violet and Iris travel to the decrepit Ames mansion, avoiding dangerous pitfalls and traps in order to retrieve the missing town key. But where will their search for the town key lead them? And once found, what will the town need to do in order to reinstate Elizabeth Zisk?