Un detective y un médico forense unen fuerzas para resolver una serie de horribles asesinatos en el Londres victoriano, pero uno de ellos alberga un secreto mortal.

Clare and Anna are devoted sisters who live together. Clare suffers from fits and Anna cares for Clare between time at work and seeing her boyfriend. However when Clare begins to see ghostly visions within the house Anna has difficulty believing her. As the visions worsen they test Clare's sanity, until one night she mistakenly attacks Anna - believing her to be one of the ghosts. Clare is hospitalised but the visions continue to haunt her. But Clare was never the true target, the spectres were after Anna and her unborn child all along. Now Clare must find out how to protect her sister, while locked up in a secure psychiatric facility.