A team of investigators explores claims the Wests were responsible for many more murders than the 12 women and girls they are known to have killed. 

This series, shown on consecutive nights, features former detective chief inspector Colin Sutton, investigative psychologist Donna Youngs, author and West expert Howard Sounes, and reporter Sir Trevor McDonald following up new leads to try to shed new light on the true number of the Wests' victims and their identities.