Set in both 1973 and the early 2000s, Steeltown Murders centres on the hunt to catch the killer of three young women in the Port Talbot area and the remarkable story of how - in the first case of its kind - the mystery was solved almost 30 years later using pioneering DNA evidence.
The drama has been written by Ed Whitmore, who's already brought us real-life crime dramas - Manhunt with Martin Clunes and Rillington Place - and is made by Severn Screen, the company behind The Pembrokeshire Murders and Hidden/Craith.
You'll recognise so many faces in this series, which runs for four episodes, including Philip Glenister, Steffan Rhodri, Stella's Karen Paullada, Pembrokeshire Murders' Oliver Ryan and Keith Allen and original Broadchurch murderer, Matthew Gravelle.
The drama also introduces (relative) newcomers Calista Davies and Jade Croot as the two girls whose tragic murders viewers will see took decades to solve.
And you'll find loads more information about the drama, including the real-life story behind it, how they made it and how the stars approached their real-life characters, here.
Read more: All the massive TV shows made in Wales
The drama starts on Monday, May 15 at 9pm and all episodes will stream on iPlayer after the first episode has aired. For the latest TV and showbiz news sign up to our newsletter here.
Here's your essential guide to the main cast:
Philip Glenister - DCI Paul Bethell
Playing another copper, Philip Glenister is front and centre in Steeltown Murders as DCI Bethell, the man whose determination finally gets the cases solved. Philip, whose family lives down the Mumbles in Swansea, is synonymous with his epic portrayal of DI Gene Hunt from Life on Mars, opposite John Simm. Although part of Steeltown Murders is set in the 1970s, Philip isn't involved in those scenes and his detective in it, couldn't be further from the un-PC Gene Hunt.
Phil also starred in Life on Mars spin-off Ashes to Ashes, Vanity Fair, State of Play, Mad Dogs, Big School and Outcast.
Steffan Rhodri - Phil ‘Bach’ Rees
A Welsh actor who doesn't need much introduction with a long career on Welsh TV including Belonging, Keeping Faith, Yr Amgueddfa, Hinterland, Stella and roles in Last Kingdom, House of the Dragon and Wonder Woman, Swansea's Steffan is irreplaceable as Dave Coaches in Gavin & Stacey. Read more with Steffan in our big interview with the star, here.
Scott Arthur - 1973 DCI Bethell
With parts in Amazon's Good Omens, movie Borg McEnroe, Llangnnech-born actor Scott plays the younger version of Philip Glenister's character. Scott has also provided voices in several video games, including Elden Ring.
Siôn Alun Davies - 1973 Phil Rees
The co-lead (with Sian Reese) in BBC's Hidden/Craith, Sion has also been in Netflix's The Sandman, BBC's Requiem and Welsh horror, The Feast.
Richard Harrington - Colin Dark
Merthyr's Richard is another Welsh actor with a long-standing career on TV, one of his biggest roles being DCI Tom Mathias in Hinterland. But he's also been seen in Poldark, Death in Paradise, The Crown, Gangs of London and in the recent big screen sequel, Fisherman's Friends: One and All. In Steeltown he's Colin Dark, who studies the DNA that finally solves the murders.
Karen Paullada - DS Jackie Roberts
The Stella star is unrecognisable from her role as perma-tanned Nadine on Ruth Jones' Sky dramedy and in Steeltown she is the no-nonsense DS who pulls in Paul Bethell to try and solve the cold cases.
Here's the list of the full cast of Steeltown Murders
Nia Roberts - Karina Bethell (2002)
Elinor Crawley - Karina Bethell (1973)
Gareth John Bale - DC Geraint Bale
Priyanga Burford - Sita Anwar (2002)
Sharon Morgan - Pat Williams (2002)
Keith Allen - Dai Williams (2002)
Rhys Rusbatch - Dai Williams (1973)
Natasha Vasandani - Sita Anwar (1973)
Calista Davies - Geraldine Hughes
Jade Croot - Pauline Floyd
Kriss Dosanjh - Rohan Anwar
Mathew Gravelle - Seb
Richard Corgan - DS Chris Lewis
Oliver Ryan - DS Ray Allen
Dyfan Dywfor - DS Vic Jenkins
Steve Nicolson - DI Tony Warren
Aneurin Barnard - Joseph Kappen
William Thomas - Denver Hughes
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