Actress Katherine Kelly hosts the true crime series examining crimes that rocked a particular city. The second run begins with a case in Portsmouth.

This episode explores two terrible crimes that left a lasting impression on Hull - and reveals how complex investigations into one case finally led to both mysteries being solved. The story begins with the apparent kidnap and murder of Christopher Laverack, a crime that initially had police stumped. It would remain unsolved for years. We also tell the story of the disappearance of Joanne Nelson, who vanished from the city on Valentine’s Day, 2005. It was a story that had the whole city on edge and led to the biggest search in Humberside Police history, before a breakthrough led police to finding her killer, and the whereabouts of her body.

In 1993 a sixteen-year-old girl is found dying by the side of the road. Her killer disappears into the night. Her name is Claire Tiltman, and as police investigate they learn she's a girl with no enemies, and the crime is motiveless. There's no sexual attack, and no robbery. But there is extreme violence. Two years later, another attack is committed on a young woman. This time, locals identify the town milkman, Colin Ash Smith. Police investigate, and find a diary with details of crimes he's committed and crimes he plans to do. In his car they find half a school-tie, part of a weapon he used on an earlier crime seven years earlier. He's jailed for two attacks, but not Claire's murder. It takes over twenty years before he's finally brought to trial, following advances in forensics, and found guilty of killing Claire. Jurors hear of how he knew Claire, and even went to her funeral.

In this episode explores how one boy left an entire city living in fear. Aged 15, Robbie Mcintosh walked into a fish & chip shop to announce that a woman had been killed on the iconic Law Hill. Locals were terrified as the news spread. Police revealed the victim had been stabbed dozens of times. But police never imagined that the culprit was a 15 year-old. As cops swooped to arrest him, Mcintosh fled to Glasgow airport, buying a ticket to Canada when he was placed under arrest. Was Mcintosh a local youth who had committed something shocking, or a serial killer in the making, stopped in his tracks? Dundee would find out in 2017, when Mcintosh was allowed out of prison on home leave. He lasted 5 days. Then he took a walk into nearby woods, spotted a female dog walker, and attacked her with a large heavy dumbbell. The woman survived, and police arrested Mcintosh just an hour later. In Dundee, lightning had struck twice terrifyingly, Mcintosh will be eligible for release in 2022.

In 2015 a 69-year-old man is found stabbed in his own home. Cops can't understand it. There's no forced entry. And no obvious motive. He has no enemies. At the scene, forensics uncover a receipt from a nearby cashpoint. Cops think it will narrow down the time of death. But they're in for a shock. CCTV at the bank reveals a woman, using the victims card to withdraw cash. Who is she? And how does she relate to the murder? It turns out that her boyfriend, Ian Birley, is a man with a past. He's only been out of prison a year, after serving a life sentence for an almost identical murder. Back in 1995, while living on the streets in the town, Birley had killed an elderly man in his own home, for no real motive. Now lightning had struck twice.

In 2014 a local woman goes missing after a night drinking in the pubs of the town. CCTV finds her walking home, arm in arm with another local drinker. He just happens to be a former butcher. Police soon realise he has put his trade to use, by dismembering his poor victim and hiding her body parts around the town. It's a crime with no obvious motive, and one which shocked the whole community. He was a man with a past – he once set fire to his primary school, and was found by firemen sat in the middle of the blaze paying the piano. It's a dark story – that we're still unpicking. Pontypridd is labelled the murder capital of Wales for the volume of crimes there in recent years.

1994 an evil gang kill a woman who manages a building society and tie up her husband, before robbing the building society of large sums of cash. Cops are baffled. But something doesn't quite add up. Despite making a tearful plea for help, the injured husband's story doesn't tally. Cops soon start to suspect that the ‘gang' are a hoax, and that Gordon Wardell has murdered his wife Carol in a bid to get money.

In 2000 a young woman is stabbed to death while walking her dog in a picturesque park in the town. She's a twin, a woman known in her local area. A suspect is seen running semi-naked across the M1 motorway and makes his escape. Cops initially suspect the killer of Rachel Nickel might be responsible...and it takes detectives weeks to identify the real killer is a local man called Leon Amos. They find out his family are known criminals, who have been covering Leon's tracks, and that the killer may have mistakenly carried out an act of retribution on the wrong twin.

In 2014 a sex offender called Robert Hind goes missing from a bail hostel. Cops fear he's absconded to commit crime. The town is scoured. Then cops find CCTV of the man with another ex-con called David Mitchell at the bus station. They find out the two men are friends, who live together at the hostel. Rumour has it they are in a relationship together. They fear the two men have gone to do something terrible. But then they learn that the sex offender hadn't absconded, he's been murdered, by Mitchell, the man with him on CCTV. Mitchell has killed before – murdering his wife in the 90's. Now he's killed paedophile Hind, and dumped him in the canal. It's a canal that contains many dark secrets, as we also see from the story of Tobias Minski, a student in Huddersfield who disappeared and sparked a town-wide search, before his body was found folded up in a suitcase beside the canal.

Throughout the early 90s young boys would be found dead after sniffing glue and being trapped in derelict buildings which caught fire. But when it kept happening, cops got suspicious. They soon found they were actually being systematically murdered by a man called Steven Grieveson, dubbed the Sunderland strangler in a case which still haunts the town. His is a name few will know, but he's regarded as one of the most dangerous killers in the UK.

In 2015 a man visits a tarot card reader. Within an hour she's dealt out the death card and he's confessed to a murder. When cops arrive they discover he's been living at home with his victim's body for days. Both men are a part of the spiritualist church - and have fallen out in the biggest way possible. Cops have the grim task of investigating the crime, and proving the death is a murder. This episode taps into a series of crimes with same-sex partners committing murder in the city and living with their victims, and we tell the story of a second crime, with very similar outcomes, that saw a man go on the run for a year.