In the early years of the 20th century, the Kingsman agency is formed to stand against a cabal plotting a war to wipe out millions.

A support group of killers is held regularly. The participants sit in a circle of trust and share their transgressions.

The story is set in 1947, following a long-retired Holmes living in a Sussex village with his housekeeper and rising detective son. But then he finds himself haunted by an unsolved 30-year old case. Holmes memory isn't what it used to be, so he only remembers fragments of the case: a confrontation with an angry husband, a secret bond with his beautiful but unstable wife.