"The Amethyst Box" by Anna Katharine Green is a mystery novel written in the early 20th century. The story is set against the backdrop of a wedding eve and explores tension-filled circumstances leading to a potential tragedy involving love, jealousy, and deadly secrets. The primary characters include Sinclair, the anxious groom; Walter, his loyal best man; and Dorothy Camerden, the woman whom Walter secretly loves, all of whom are drawn into the dark intrigue surrounding a mysterious vial of deadly poison. The opening of the novel unfolds on the night before Sinclair's wedding, where he confides in Walter about a missing vial containing a potent poison, which has mysteriously gone missing after he showcased it to the ladies present. Sinclair's fears escalate when he reveals that one of the two women—either his bride-to-be, Gilbertine, or Walter's love, Dorothy—has taken it. As they attempt to uncover the truth, the atmosphere thickens with suspense and dread, setting the stage for a story steeped in psychological complexity and moral ambiguity as they navigate the unknown ramifications of this critical moment. (This is an automatically generated summary.)