While Cambridge police detectives interview witnesses who may or may not tell the truth, 'Sam' extracts revealing truths from calcified bones, decomposed and charred bodies, tell-tale bruises and overlooked fingerprints. Brace yourself for twists and turns in four gripping episodes: the suspicious drowning of a six-year-old girl, the apparently ritual killing of a young man, a death in police custody, and the fiery murder of a refugee's business partner.