The character of Mary Watson first appears in Arthur Conan Doyle’s The Sign of Four (1890). Scholars have read Mary as a personification of late nineteenth-century British imperial and societal anxieties. Mary is identified both with the dangerous colonial Other and New Woman and, conversely, with the “pure” and safe British domestic order that uneasily triumphs over these threatening forces. Though the critical discourse on Conan Doyle’s work acknowledges the ambivalence surrounding Mary, many critics ignore her eventual childless death in the original Holmes canon. Considering Karen Beckman’s study of the Victorian “vanishing woman” magic act, Mary’s death can be interpreted as this sort of “vanishing”—one that further resists the uneasy containment of the threats so often read in Conan Doyle’s novel. In the television series Sherlock (2010–17) created by Steven Moffat and Mark Gatiss, Mary Watson performs Beckman’s vanishing act in full, reappearing after her onscreen death. Though Sherlock’s Mary is seemingly divorced from her original Victorian context, a closer reading of her trajectory in the series suggests that the model of the “vanishing woman” is very much the same—with the historical points of context merely substituted. Sherlock’s treatment of Mary’s character in the twenty-first century, then, seems surprisingly even more inhibitive and violent than that of Mary’s character in its nineteenth century source material.