On their first night in Paris, the Gamache family gathers for dinner with Armand's godfather, the billionaire Stephen Horowitz. But the dazzling evening ends in horror when Stephen is grievously injured. Was it an accident, or a deliberate attempt on an elderly man's life?

When a strange key is found in Stephen's possession it sends Armand on a desperate search for the truth that will take him from the top of the Eiffel Tower to the bowels of the Paris Archives.

As Armand uncovers secrets his godfather has kept hidden for decades, he finds himself ensnared in a web of lies that threatens to destroy everything - and everyone - he holds dear. The City of Light casts long shadows,