London police detectives Cassie Stuart and Sunny Khan investigate historic cold cases involving missing persons, murder and long-hidden secrets.

Nicola Walkeras DCI Cassie Stuart
Sanjeev Bhaskaras DS Sunil 'Sunny' Khan
Sinéad Keenanas DCI Jessica 'Jessie' James
Carolina Mainas DC Fran Lingley
Jordan Longas DS Murray Boulting
Lewis Reevesas DC Jake Collier
Pippa Nixonas DC Karen Willetts
Georgia Mackenzieas Dr. Leanne Balcombe
Peter Eganas Martin
Trevor Eveas Sir Phillip Cross
Chris Lang