Hidden in 18th-century London, Nella runs a secret apothecary shop, dispensing poisons to women to liberate them from abusive men. She follows two rules: never use the poisons against another woman, and record every name in a register. Centuries later, Caroline, a historian on a solo trip to London, discovers an antique apothecary's bottle while mudlarking. Her discovery begins to unravel the mystery of the unsolved "apothecary murders" and connects her life to Nella's and a young apprentice named Eliza, setting three lives across time on a dangerous collision course. This debut novel is a captivating blend of historical fiction, mystery, and a tale of female empowerment and revenge.