Returning to Syndicate 9 after a year with Vice, Rachel (Suranne Jones) needs some time to rekindle her neglected friendship with Janet (Lesley Sharp), but the shocking murder of Michael Edgerton forces her to hit the ground running as she steps up to Acting DI under the watchful eye of Julie Dodson (Pippa Haywood). When a teenage boy sees a clip of Michael’s murder on the darknet, it’s clear that Syndicate 9 are dealing with something much bigger and more sinister than a single, indiscriminate murder. A sick game is being played and Syndicate 9 need to find the next potential victim before the killer does. Glad of Rachel’s return, Janet couldn’t have known how much she was going to need her friend. When Taisie (Harriet Waters) is arrested, setting off an inconceivable chain of events, Janet is thrown into turmoil and Rachel’s wisdom and experience are exactly what she needs to steer her through the crisis.
When the body of teenager Will Hudson is found in a Manchester park, Rachel (Suranne Jones) knows his death could have been prevented. With information about the Taking Out The Trash website in the public domain, monitoring potential targets is severely compromised and Mitch’s missing daybook seems the likely source of the leak. When Rachel receives an email with video footage of Will’s murder, it’s clear the rules of the game have changed and Rachel’s safety is in question. Acting as appropriate adult in Taisie’s (Harriet Waters) police interview, Janet (Lesley Sharp) feels powerless to protect her daughter. Rachel tells her that as a police officer, she mustn’t interfere, but Janet is Taisie’s mum first and knows she has to do something to stop the madness. At the end of Syndicate 9’s darkest day, Janet and Rachel share a drink, and it’s clear to Janet that the world is now a very different shape.
Rachel (Suranne Jones) is criticised for the lack of progress in the investigation and with Steve Dench (Richard Riddell) still the prime suspect, she knows she must find both a murder weapon and the encryption code used to access the Taking Out The Trash website. Then, they not only get Steve for multiple murders, but they also find the man he’s playing his sick game with. Discovering that the witness at Michael Edgerton’s murder may be one of the killers marks a big breakthrough, and with the attacks increasing, Rachel hopes that the killers will start to make mistakes. The appearance of a star on Rachel’s gatepost terrifies Alison (Sally Lindsay) and when Julie Dodson (Pippa Haywood) finds out, Rachel’s position as Acting DI is jeopardized. But with new evidence challenging Steve’s alibi and a positive ID of the witness, Rachel is determined to hang onto the case. When Janet’s (Lesley Sharp) attempt to help Taisie (Harriet Waters) results in a complaint, her faith in doing everything by the book is rocked, and with Rachel’s pregnancy out in the open, both Scott and Bailey have life-changing decisions to make about their futures.