When Gary Allen is acquitted of murdering Samantha Class in 2000, detectives know it's only a matter of time before he strikes again. In 2019, the murder of another woman, Alena Grlakova, leads detectives once again to Gary Allen, unearthing chilling evidence which changes the course of the investigation and entwines Alena and Samantha's cases forever. Can he finally be brought to justice?