In 1982, the first victims of America's most prolific serial killer were found. The killer was at large for two decades, amassing a body count of over 50 women. Catching him took an advance in 'forensic microscopy' to indisputably link minute paint particles from the victims' clothes to the killer.

In 1999, detectives investigate the body of a murdered woman found in a barrel along with an address book that had been soaked for over 30 years. Using a game-changing technology called spectral imaging, scientists recover the information from the address book, giving the cops the break they need.