Though they live fulfilling, independent lives in three different countries, Olivia Segal, Jamie Arias and Annie Aldrich Thomas remain bound to each other by a past tragedy - and by their pact always to be there for each other at times of great need.

In a London vault lies a story waiting to be read; a tale of evil more than fifty years old, a link with the past and a present danger more terrifying than anything the friends could have dreamed up in their wildest nightmares.