England| 1872. The night before he is to be hanged for a murder he did not commit| young Dr. Gordon Ramsey is visited in his cell by his old mentor| eminent surgeon Sir Joel Cadmund. Cadmund offers to see that Ramsey gets a proper burial and gives him a sleeping powder to get him through the night| which Ramsey takes| unaware it is really an East Indian drug| “nind andhera” (“the black sleep”)| which induces a deathlike state of anesthesia. Pronounced dead in his cell| he is turned over to Cadmund| who promptly revives him and takes him to his home in a remote abbey. Cadmund explains he believes Ramsey is innocent and needs his talents to help him in an project| which he is reluctant to immediately discuss further. In fact| Cadmund’s wife lies in a coma from a deep-seated brain tumor| and he is attempting to find a safe surgical route to its site by experimenting on the brains of others| whom Ramsey comes to learn are alive during the process| anesthetized by the “black sleep”| and …