When Mahalia’s body turns up close to the border between Besźel and Ul Qoma, Inspector Borlú is surprised by the similarities to an old case that still haunts him.

As he fights to uncover the truth behind Mahalia’s death, Borlú crosses over a border like no other to work with the Ul Qoman Militsya, challenging everything he holds dear.

Borlú is caught up in a dangerous underworld. As he faces the demons of Katrynia’s past, anyone connected to the fabled third city, Orciny, is increasingly at serious risk.

Under the vigilant eyes of Breach, Borlú doggedly chases the truth about what lies between the city and the city, making a devastating discovery that changes his life forever.