On December 30th, 1970, at the age of 38, former heavyweight champion Sonny Liston died from what Las Vegas police suspected was a heroin overdose. When police arrived, they found a one-ounce balloon on Sonny's nightstand but the coroner quickly labelled Sonny's passing as death by natural causes. To this day, Liston's death hovers over Las Vegas and the sports world, leaving unanswered questions about his ties to powerful boxing promoters, billionaire hoteliers, mob kingpins and shadowy drug lords. Reviving boxing's most infamous cold case to work out what really happened on that night in December over forty years ago, Shaun Assael examines the last mysterious year of Liston's life against the backdrop of a pivotal year in the history of Las Vegas. 1970 was the year that the mob turned a sleepy desert oasis into a cathedral of corporate gambling. Glittering new towers were rising along the strip, while race riots were devastating the black community, creating two very different cities for Sonny Liston to disappear into. With key aspects of Liston's life previously ignored or glossed over, Assael takes a fresh look at Liston's complicated life, getting to the bottom of one of America's most enduring mysteries, while painting a stunning portrait of mob-run Las Vegas in the 1970s.