Owney “Killer” Madden started out his career in crime with Gangs of New York outfit The Gophers before moving up in the world to open and own the world-famous Cotton Club. At his peak he controlled most of the speakeasies and drinking dens in Hell's Kitchen before moving out of drink into Boxing promotion. In 1932 he was involved in the murder of another Irish Mobster and retired to Hot Springs, Arkansas where he lived a quiet life until his death in 1967. His weekly card game included Bill Clinton’s father! John "Red" Hamilton was the number 2 to notorious gangster and America's most wanted John Dillinger who carried out many bank raids and ran rackets along the Canadian American border during the 1930s.

Mickey Spillane was known as "the last of the gentleman gangsters." He ran the rackets in the Hell's Kitchen neighborhood of New York and was married to the daughter of the most powerful political family in the district. For decades he waged a war with the Mafia for control of Hell's Kitchen, but when Spillane was finally murdered, it wasn't the Italians who pulled the trigger but a vicious new generation of Irish gangsters. In New York in the 1980s a crew of Irish gangsters emerged as one of the most feared gang of killers the city had ever seen. They called themselves The Westies, and they were led by the wildest Westie of them all - Jimmy Coonan. Under Coonan's leadership, the Irish Mob butchered and shot their way to the top of the criminal rackets until the streets of Hell's Kitchen ran red with blood.

Danny Greene was known as the Celtic Warrior. He ran a criminal empire in Cleveland and took on the might of the Italian mob there with no fear at all. His bravery was to be his downfall as the mafia finally managed to blow him up after a rushed meeting to a dentist for a sore tooth. For over thirty years Jimmy “The Gent” Burke was one of the most powerful criminals in New York city. He was the basis for Robert De Niro's character in the film “Goodfellas,” which charted the relationship between Burke and another up-and-coming gangster - Henry Hill. In an exclusive interview Henry Hill reveals the true story behind his and Burke's exploits and how together they managed to pull off one of the biggest heists in US history - The Lufthansa Heist.

Based in Canada, the Stopwatch Gang got their name from the FBI as its leader always wore a stopwatch around his neck, and all bank robberies lasted no more than 90 seconds. They were made up of 2 Irish Canadians, Paddy Mitchell and Steven Reid, plus Lionel Wright. They are credited with over 100 robberies from California to Ottawa via San Diego and got away with an estimated $25 million by 1985. The West End Gang were led by Frank “Dunie” Ryan and were (still are) Montreal’s most notorious criminal organization. Ryan started out as a petty criminal and served 6 years of a 15-year sentence in prison. On his release he decided that drugs were the new way forward, and he founded the West End Gang. He went on to become one of America’s largest Cocaine importers through Canada. At his death in 1984, he was worth an estimated $100 million.

o Pat Nee started out with James “Whitey” Bulger in the Winter Hill gang in South Boston. As Whitey started to introduce drugs to the community, Nee tried to stop it, and eventually they parted ways and became arch enemies. Nee, born in Connemara, moved with his family to America when he was 7. He became a hitman after coming out of the Marines after Vietnam when he returned to Southie. He also specialized in armed robberies. He tells us firsthand about his criminal career and brings us around to the places where he hung and carried out some of his crimes. He also explains how he arranged the shipment of 15 tons of guns and ammo to the IRA on the Valhalla, which was caught off the Irish Coast in 1984. Brian O’Dea tells his own incredible story, starting as a small-time hash dealer before becoming the largest Cannabis importer into Canada. This led him to organizing his own flights from Colombia & Bolivia now stacked with cocaine. Countless crashes into Amazonian forests, the Caribbean, and over the Great Lakes never seemed to stop him, the drugs just kept on pouring in. An incredible first-hand account of what it is like to be a major drug importer and how it can ruin many lives.

In a deathbed confession, Frank “The Irishman” Sheeran revealed his role in one of the great unsolved mysteries of the twentieth century: Who killed Jimmy Hoffa? Sheeran worked as a Mafia hitman for over thirty years, and his story links the events that surrounded the Mob's suspected involvement in the Kennedy assassination and the eventual disappearance of Jimmy Hoffa, a hit that was carried out by The Irishman himself. Prior to his arrest Bulger was America’s Most Wanted criminal. He ruled South Boston or Southie as it was known. James “Whitey” Bulger was America’s most wanted until his arrest in June 2011. We hear from his former right hand man Kevin Weeks whose testimony led him to be convicted of 19 counts of murder.

In the 1970s, the Boston underworld is in chaos. Dozens of Irish neighborhood gangs have spent decades brawling over turf, creating a power vacuum. But one Machiavellian foot soldier will scheme and kill his way through the ranks to become the most famous gangster in Boston history, leaving a unified Boston Irish Mob and the longest manhunt in U.S. history in his wake.