Shetland series 9 lands on BBC One and BBC iPlayer this week, and DI Ruth Calder and DI Alison 'Tosh' McIntosh investigate when a woman and her young son goes missing.

The new season of the show sees Scottish actress Ashley Jensen return in the lead role for the second season running.

Of course, fans of the show will know that she replaced Douglas Henshall's DI Jimmy Perez who left at the end of series 7 (after nine years on the show).

While some doubted the show could survive without the popular lead detective Perez, the series "refresh" has actually proven quite the hit.

Here's everything you need to know about Shetland series 9, including plot, episode 1 preview, location, cast, and start date.

What is the plot of Shetland series 9?

In Shetland series 9, Calder and Tosh - newly promoted to the position of Detective Inspector - are forced to investigate when a mum and her son go missing.

Tosh is devastated when her own friend, Annie Bett, seems to vanish into thin air. Knowing that something must be seriously wrong, Tosh and Calder set out in search of Annie and her young son, Noah.

A BBC synopsis tell us: "A double missing persons case blurs the line between the personal and the professional, as Calder and Tosh are drawn into a labyrinthine investigation."

After the dramatic events of Shetland series 8, DI Ruth Calder is now living in Shetland. And she has no time to recover from a life-threatening ordeal of her own as she's thrown into another case.

Tosh and Calder discover that accountant Annie is estranged from her husband, Ian, and has been staying with mussel farmer John Harris and his two sons, Patrick and Fergus. But there's no sign of her there either...

When the detective duo visit the home Annie shared with her estranged husband Ian, they discover Professor Euan Rossi. He claims to have been Annie's Oxford University tutor many years ago. He travelled all the way to Shetland after Annie left him a distressed voicemail the night she vanished...

But is there more to Rossi than meets the eye? When a bloodied person turns up at a remote garage, nothing can prepare the team for what lies ahead.

Running parallel to the missing persons case, Calder looks into another case involving a deadly argument between two brothers.

Shetland series 9 preview: What happens in episode 1?

In episode 1 of Shetland series 9, we see DI Ruth Calder talking to Malcolm Kidd, a jittery young man holding a shotgun. His brother's dead body lies on the floor between them. Tosh and the rest of the team are waiting outside.

Later that night, Tosh attends her friend's birthday party and witnesses the argument of two married friends, Annie and Ian Bett. Their nine-year-old son, Noah, tells Tosh his parents are separating.

Before they leave, Annie arranges a meeting with Tosh the next morning – she wants to speak to her about something important. Annie and Noah are staying with John Harris, a mussel farmer, and his sons Patrick and Fergus.

But when Tosh arrives the next morning, there's no sign of Annie's car, and she's not picking up her phone. Where are Annie and Noah?

When does Shetland season 9 start? How can I watch it?

Shetland series 9 will start on Wednesday, November 6, 2024 at 9pm on BBC One and BBC iPlayer.

Each hour-long episode will air every week until the finale, which is expected to go out on Wednesday, December 11, 2024 at 9pm.

All previous series of Shetland are currently available to watch on BBC iPlayer.

Who is in the cast?

Ashley Jensen and Alison O'Donnell return for a new series of the acclaimed murder-mystery drama, Shetland.

Scottish actress Ashley Jensen will be back as Detective Ruth Calder. Ashley is known for her roles in Ugly Betty, Agatha Raisin, After Life, and Catastrophe.

Alison O'Donnell also reprises her role as Alison 'Tosh' McIntosh. She's been on the show ever since it started in 2013, and was her sixth ever TV role.

Joining Ashley Jensen and Alison O'Connell in the cast are Outlander actress Sarah MacGillivray as Annie, and newcomer Jacob Ferguson as her son Noah (in his first ever TV role).

Meanwhile, Annika actor Robert Jack plays Ian Bett.

Ian Hart will be playing suspect Professor Rossi. Of course, Harry Potter fans will know the actor as Professor Quirrell, but his recent TV roles include Mr Bates vs. The Post Office, The Mosquito Coast, and The Responder.

House of the Dragon's Vincent Regan is John Harris, while Granite Harbour stars Ross Anderson and Macleod Stephen are Patrick Harris and Fergus Harris.

Of course, Steven Robertson returns as Shetland copper DC Sandy Wilson. Other cast members include Lewis Howden, Anne Kidd, Angus Miller, Steven Miller, Leeroy Boone, Conor McCarry, Eubha Akilade, Stuart Campbell, Nalini Chetty, Richard Thomson, Tibu Fortes, Andrew John Tait, Tara Lee, Jimmy Yuill, Lesley Hart and Gemma McElhinney.

Where is Shetland series 9 filmed?

As the name suggests, Shetland is filmed in the Shetland Isles, in the Northern Isles of Scotland.

Previous series has seen the cast filming in Lerwick, the capital of the Shetland Islands and the only town in the entire Isles.

In the past, shooting has also taken place in the Lodberries area, and in particular on Commercial Street, according to the Shetland Times.

Camera crews have also been spotted on Wester Quarff, a small village five miles south of Lerwick.

Filming often takes place on mainland Scotland, too. Scenes have been filmed in areas with landscape or buildings reminiscent of those in the Shetland Islands, such as Kilbarchan in Renfrewshire, Barrhead. Also, Ayr and Irvine, North Ayrshire.

According to reports, filming locations for Shetland series 9 include Lerwick. The Lerwick Police Station and court buildings are used for external filming.

Brae, and Wester Quarff - a village south of Lerwick - will also feature.

Shetland season 9 will start on BBC One and iPlayer from Wednesday, November 06, 2024 at 9pm.