The second season, which kicks off this February, will continue to follow the women of the Scottish Institute of Forensic Science (SIFA) as they attempt to solve a series of bombings in Dundee. A second season teaser adds: "The city is on edge as the pressure rises to identify the mystery bomber before the next bomb goes off."
Season 1, which also aired on BBC One, focussed on Windsor's character Emma, whose mother Marie was murdered when Emma was just seven years old. However, when the now grown-up Emma makes a new start in Dundee, she comes across her mother's as-yet unsolved murder case in the most unexpected way.
Speaking about the new series, Compston told RadioTimes.com: "[In] season 2 the story has moved on a little bit. At the end of series one Daniel had turned in some evidence against his dad and his dad had been arrested.
"We’re now just before the trial of his dad for the murder of his girlfriend Emma’s mum. You find Daniel and Emma in quite a happy place, actually, they reconciled at the funeral at the end of series one and for a split second they’re kinda happy and then the wheels start to come off a bit…"
Read on for everything you need to know about the cast and characters in Traces.
Molly Windsor plays Emma Hedges
Who is Emma Hedges? A 23-year-old who, at the start of season 1, signed up to a MOOC – Massive Open Online Course – which teaches the principles of forensic science. However, she soon realised a supposedly fictional forensic case study bore a remarkable similarity to a real-life case she knew all too well: her mother's unsolved murder.
Where have I seen Molly Windsor before? The actress is known for roles in Three Girls, The Unloved, The Runaways, Cheat (as Rose), and Make Up.
Laura Fraser as Prof. Sarah Gordon
Who is Professor Sarah Gordon? Professor of Chemistry, she's taught the very case study that raised Molly's suspicions back in season 1.
Speaking about the female-led series, Fraser told RadioTimes.com: "This wasn't even 50/50 – it was actually predominantly female and I really appreciated it, it felt so comfortable."
She added: "I would love to see more of that. It'd be great if the pendulums swings, and then balances out so it's 50/50 – that would be incredible."
Where have I seen Laura Fraser before? She played Lydia Rodarte-Quayle in both Breaking Bad and Better Call Saul. She's also starred in The Missing, A Knight's Tale with Heath Ledger, The Loch, and Doctor Who.
Jennifer Spence as Prof. Kathy Torrence
Who is Professor Kathy Torrence? Professor of forensic anthropology, and a colleague of Sarah's.
Where have I seen Jennifer Spence before? Spence has starred in the likes of Continuum, Close Up, Trigger Me, Family Law, and You Me Her.
Martin Compston plays Daniel
Who is Daniel? A man whom Emma meets in season one and shares a romantic connection with. At the end of season 1, (spoiler!) he turned on his own father for potential murder.
Where have I seen Martin Compston before? He's best known for playing Steve Arnott in Line of Duty, but he's also starred in surrogacy thriller The Nest, Sweet Sixteen, Mary Queen of Scots, and Monarch of the Glen.
John Gordon Sinclair plays Drew Cubbin
Who is Drew Cubbin? Emma's father, whom she reconnects with during the first series.
Where have I seen John Gordon Sinclair before? The Glasgow-born star played Gregory in the iconic Scottish film Gregory's Girl, and has gone on to star in Erik the Viking, World War Z, and Mad About Alice.
Laurie Brett as Izzy Alessi
Who is Izzy Alessi? A figure from Emma's childhood, and her best friend's mum.
Where have I seen Laurie Brett before? She played Jane Beale in EastEnders and Christine Mulgrew in Waterloo Road. She's also starred in London Kills and the recent Deadwater Fell as DC Gemma Darlington.
Vincent Regan as Phil Macafee
Who is Phil Macafee? Daniel's father, who was arrested at the end of season 1.
Where have I seen Vincent Regan before? He's known for appearances in films like 300, Snow White and the Huntsman, and Troy. Regan played Ned Despard in Poldark, Jasper Tudor in The White Princess, and Tony in Flesh and Blood.
Traces season 2 begins Tuesday 15th February 2022 on Alibi. Traces season 1 is now available to stream on BBC iPlayer. Find something to watch tonight with our TV Guide