The Met

In Brixton, south London, a man's body is found in the bushes of a park. He is identified as 44-year-old Mauricio Nascimento, who was homeless at the time of his murder. According to the pathologist, it is the most vicious attack he has ever seen – Mauricio has been kicked and stamped to death.

Detectives from the Met's murder investigation team must find his attacker. The murder took place in an area used by rough sleepers and not covered by CCTV, usually a vital tool in police investigations. The team must rely on forensic evidence and hope there are witnesses to the crime. However, questioning of the rough sleepers who use the park produces contradictory stories and rumours but no firm leads.

Two days after the murder, detectives discover what they believe could be a breakthrough. An analysis of Mauricio's financial records reveals his bank card was used after he was murdered. Detectives identify the man who used the card and arrest him, believing he may have killed Mauricio to steal the card. However, under questioning, the man says he was a friend of Mauricio's and had nothing to do with the murder. As further evidence confirms the man's story, he is released, leaving detectives with few leads while an extremely violent killer remains free.

In Hounslow, north west London, a woman goes to police saying she was raped in the early hours of that day. She tells them that after a night out drinking with friends, she became unwell outside the house she was staying in. A man offered to help her, but she blacked out. When she came to, she was inside his house, and he was raping her. With details provided by the woman, the police identify the man, and he is arrested. Under questioning, he denies raping her and claims it was she who forced herself on him. Police now have 24 hours to either find enough evidence to charge or release him.

In Brixton, south London, Shane Jerome was working as a motorcycle stuntman for a music video shoot when he was attacked and stabbed through the heart. His girlfriend witnessed the attack and was at his side when he was pronounced dead. Detectives from the Met's Murder Investigation Team must find his killer. The murder took place in one of London's busiest streets, extensively covered by CCTV. As detectives trawl through images of the incident, they spot the masked attacker touching one of the sports cars being used in the shoot. If forensic experts can lift a print from the car, it may give detectives the vital clue they need to identify Shane's murderer.

In Wimbledon, south west London, response officers Jay and Sade receive a 999 call reporting a man attacking a woman in the street. A witness has reported seeing knives, so Jay searches the man's house where he finds drugs and cash. A further search of the man's garden leads to the discovery of a shotgun. Another 999 call sends them to the house of a 60-year-old woman who is threatening to kill herself with a gun.

A man is wanted in connection with the rape of a 12-year-old girl, but he's gone on the run. The Met's Predatory Offender Unit specialises in tracking down dangerous fugitives and is brought in to find him. As he uses multiple identities, they begin a digital surveillance operation they hope will give them a lead. The team also searches for a suspect who has committed multiple sexual assaults in recent weeks. They fear his crimes will escalate and are in a race against time to catch him before he offends again.

In Harrow, north west London, an elderly couple are burgled and attacked by three men in their own home. The men are members of a criminal gang that has been active in the capital for over 18 months, targeting vulnerable and elderly people for their jewels and cash. The gang are experts at leaving no trace behind them: they wear gloves to prevent leaving fingerprints, masks to hide their identities and use bleach to clean up the crime scene. Although detectives believe they know who the men are, they don't have enough evidence to be able to charge them.

To try to stop the gang they call in the Flying Squad, an elite team of covert officers, who specialise in armed surveillance and the ambush. The only way to gather enough evidence to secure a conviction is to catch the gang in the act, while committing a burglary. Covert Flying Squad officers begin a surveillance operation they hope will finally bring down the crime network.

In Islington, north London, officers from the online child sexual abuse and exploitation unit arrest a man in his 20s suspected of possessing indecent images of children. He denies having deliberately downloaded the images, claiming it was an accident. The team must view and assess thousands of images on his hard drive to gather the evidence to charge him. In south London, they arrest another man also suspected of possessing indecent images. When they arrive at his house, they discover he lives with his partner and baby. They must urgently safeguard the child and establish whether as well as viewing images, he has been creating original content by abusing children himself.

In Camden, North London, a woman reports being sexually assaulted in the street. She provides police with a very precise description of the perpetrator: male, black cap, glasses and wearing a black tutu. His distinctive dress tells detectives he is responsible for at least 8 reported incidences of sexual assault and indecent exposure in the area over two years without getting caught. As there is no forensic evidence and no CCTV of any of the offences, officers have few leads.

Weeks later, a member of the public comes forward with the identity of a suspect who matches the description given by police. He is arrested and a search of his house reveals a black tutu. However, while he is in custody there is yet another assault by a man in a tutu – the suspect in custody is ruled out and released without charge. Two years after the first attack, police still have few leads. They believe it is only a matter of time before he strikes again.

In Hackney, East London, an 87-year-old woman is assaulted and robbed outside her home. She suffers bruising to her arm and body and is hospitalised. Detectives investigating the attack obtain CCTV of the victim being followed from the post office to her home and circulate an image of the man on social media. A member of the public identifies him as a patient at a secure mental health facility. Detectives discover that despite having nearly 100 robbery convictions – including many against elderly women – he had been given unescorted leave on the day of the attack.

In Newham, East London, response officers Laura and Omar are on a night shift when they are called to an incident: a woman is shouting for help outside her flat. She has stopped a passing car and told the occupants she's been beaten up by her boyfriend who is still inside the flat. Officers arrive at the address and arrest the man, but the victim chooses not to cooperate with the police, making a charge against the man difficult.