1879, London. An investigation into two mysterious deaths leads detective duo Minnie Ward and Albert Easterbrook to the doors of the Spirit Sisterhood, a female-only spiritualist group that facilitates communion with the dead. Minnie isn't buying it.

She goes undercover at the organisation's countryside home, where she finds herself drawn into the dark but strangely alluring world of spirits and ghosts. But, isolated from Albert and everyone she loves, can she find a way out before time runs out?