December 1918: Post-War London is grieving, the city a wound whose dressing was taken off too soon. Violet Hill, the only female private detective in the city, is hired by Sir Arthur Conan Doyle's business manager to uncover spiritual trickery he believes is deceiving his employer.
January 2018: Susanna is a super-recogniser, one of an elite Met Police team of officers with extraordinary powers for facial recognition. When a freak injury causes her unusual ability to suddenly disappear, a dangerous criminal whom she no longer recognises decides to close in.