In 1955, on the home straight early in the Le Mans 24-Hour race, future British world champion Mike Hawthorn made a rash mistake causing Pierre Levegh's Mercedes 300 SLR to smash into the crowd, killing 83 people and injuring 120 more. It remains the worst disaster in motor racing history and he story was quickly engulfed by conspiracy theory, blame and scandal. Was the uncharacteristically large explosion caused by Mercedes gambling on untried technologies? Have the French authorities been covering up the truth ever since? Or was Hawthorn, who ended up winning the race, simply guilty of reckless driving?