Two kids from the muddy outskirts of London, hired through a burner phone, travel to a dilapidated apartment building under the pretense of killing a pedophile. But there’s something they don’t know until it’s too late: The man they’ve been hired to kill is Finn Wallace. For 20 years, Finn has sat at the head of the underworld table. His assassination at the hands of two nobodies not only creates a power vacuum among the city’s many gangland factions, but angers his temperamental son Sean to seek justice. A saga of criminal intrigue mixes ruthless action sequences with even more ruthless crime lords.

But affect business it does. The Wallace empire is nominally headed by the man who built it alongside Finn – Ed (Lucian Msamati), his best friend since their hardscrabble childhood as victims of the “No blacks, no Irish” attitude that faced their families in 50s England. His attempts to keep everything on track while they find Finn’s murderer are undone in an instant by Finn’s hotheaded son and heir, Sean, who wants retribution, as soon and as bloodily as possible. He announces the end of all factions’ freedom to operate until the killer is found.

Sean is mercilessly working to consolidate even more power. The Wallaces control everything. Their name can literally be found painted across the city skyline, as they’ve taken the expected tradition of mobsters owning construction companies to new heights by erecting skyscrapers and using the large building projects as money laundering shells. 

As Sean’s confidant and business partner, Alex explains, “Everything is a shell.” For instance, a woman like the Kurdish militant Lale can own a convenience store and use its bowels as a nerve center for her men to smuggle cash by stuffing it into Fruit Loop boxes. In fact, “Gangs of London” is a globetrotting series, leaping across the map from Turkey to Nigeria, with every location holding a secret concerning the ulterior motives of each gangster.    

In a world teeming with betrayal, Sean trusts very few people beyond his family, which includes a sister estranged from their quick and lethal mother Marian, and a wayward brother Billy who desperately wants to prove to his brother that he can help. In conjunction with the Wallaces is the Dumani family. While the aforementioned Alex runs the business side, his wary father Ed (Lucian Msamati) once acted as a confidant to Finn, and now not only monitors the Wallaces, but Alex’s interior designing sister Shannon too. Due to Finn’s assassination, the bonds once holding these families together begin to fray from distrust, backstabbing, and the unsettling secrets Finn himself held from everybody.        

This is the world that Elliot—an undercover cop trying to break into Sean’s inner-circle—walks into. A bruiser who cares for his disabled ex-boxing father, Elliot punches his way up the underworld ladder. First by helping Sean to uncover Finn’s murderer, then by quelling the many gangland factions, big and small, rising against the Wallaces. As the hunt expands, Elliot, seizes an opportunity to rise up the ranks. This is mostly achieved via two astonishing set pieces. First, a mass fight in a pub that looks scornfully at any other British pub brawl committed to film and says: “Hold my beer.” It involves a glass ashtray becoming part of someone’s face – before both are shattered on the edge of the bar – and a dart perforating more people more unpleasantly than you would have thought possible. Elliot barely has time to catch his breath before we are on to the second piece of impeccably choreographed carnage. This one involves a man mountain, a cleaver and no witnesses.

In fact, whether it’s Lale, the Albanian mafia chief—who Sean most suspects of murdering his dad—Luan or the Pakistani heroin kingpin Asif, each episode opens with a new crime boss taking their swing. In a stream of exhilarating action sequences where hand-to-hand combat matches stylistic camerawork (the showrunners haven’t met a canted angle they didn’t like), Elliot brawls against assassins and henchmen alike. “Gangs of London” is a gruesome crime series where every cracking bone is heard and every ounce of blood is spilled.

Although the violence is explicit and extreme, it is not – quite – mindless. Its victims’ fear is palpable. Sometimes, so is its perpetrators’. It is almost a living, breathing being in some scenes, most notably in the pre-assassination of Finn and in the awful knowledge that falls on Finn’s loyal henchman as Ed talks to him on the sofa towards the end of the first episode. The violence is not integral to the story – they have chosen to include it, especially in such a form – but it is not shorn of all context or consequences.

And yet the show always returns to the theme of youth maneuvering against experience. Elliot doesn’t want to be his punch-drunk father, Asif’s son is distancing himself from corruption by ironically running for mayor, and Alex finds his father’s apathetic tactics outdated. But it’s Sean trying to prove the most to his enemies, his mother, and the ghost of his dad. As one character observes, “A boy like him would burn cities just to convince the world he’s a man.” And Sean, who does burn everything in his wake, since he was a child, has worked to prove himself a man. 

In a flashback scene that summarizes the entire series, Finn hands his two pre-teen sons rifles and leads them into the woods. They come upon a steel bucket planted upside down in the ground. When Finn lifts the pail, he reveals the bloody head of a man. He orders Sean to finish the job and murder the buried enemy. The lesson: kill or be killed. And though later in life everyone fears the violently impulsive Sean, a young man visually defined by his sometimes pitch-black eyes, the new mob leader still struggles to kill. The instinct toward mercy undoes many of these characters as much as any of their murderous acts. They have no choice. They must kill. Such conclusions would undo most series, but this one doesn’t really believe that no choice exists. Instead, “Gangs of London” is a bold continuation of the mafia movie tradition, yet like the inexperienced figures at its center, the show carves its own enthralling path.

By the end, only Elliot has been granted enough humanity to make him anything more than a chess piece in the service of the plot, but there are hints elsewhere of more fleshing-out of others to come, which should keep viewers engaged during the bits where flesh itself is not flying. Sean’s weight-throwing is obviously masking some deeper doubts and insecurities; his sister Jackie is alienated from the family for reasons yet to be explored; and Ed’s son Alex seems to have some secrets. The question of quite what makes a family – how strong loyalties can be without a blood tie, how weak they can be despite them – runs underneath the whole story. If it is not sacrificed to spectacle in the coming weeks, there is going to be something really good here.