Katherine awakes in an underground cell with three other women; Jane, Natasha and Elaine. With complete amnesia Katherine and the other women have little time to wonder where they are before the arrival of the sadistic Dr Murdoch and the mysterious Handsome Man. The women soon discover they are part of a gruesome experiment with no obvious purpose. That night, Jane stays awake long enough to witness the first visit to their cell by the terrifying figure of the blood splattered Surgeon. One by one the Surgeon cuts a number into each woman's skin, a four digit number, the exact time he will return to kill them.

Each woman must piece together the dark secret behind Dr Murdoch's experiment and survive the Surgeon's nightly visitations of pain, torture and grisly murder.

Is there any way to escape? What is the purpose of the experiment and who, or what, is screaming every time the lights go out? (less info)