In a BBC press release, Bonnie Langford described her character Mel Bush’s reconnaissance mission in the 2024 Doctor Who series finale.

“Mel is still working for UNIT and is on a mission to find out more information about an enterprise they’re a little concerned about. Mel is trying to infiltrate and do a bit of spying. She tries to get all the intel and report back to UNIT and the Doctor.”

Langford doesn’t name the enterprise Mel is investigating but it’s likely Triad Technology and its leader Susan Triad (Susan Twist). Twist has appeared as various characters in every episode starring the Fifteenth Doctor after first appearing as Mrs Merridew in the 60th anniversary special Wild Blue Yonder.

The episode also features the story of Ruby Sunday (Millie Gibson), who is trying to find the birth mother who abandoned her in a churchyard as a baby.

“It’s very layered. I was so excited to read the scripts. We also have Ruby’s story unfolding. As we know, she is so desperate to find those missing pieces of the puzzle when it comes to her birth mother. The Doctor is trying to stay away from it because he doesn’t want to mess things up. So there’s a lot happening and a lot of twists and turns for the viewers.”

When asked sum up what fans can expect from the finale, Langford mentioned heartbreak.

“Let’s just say mystery, adventure, vulnerability, emotion and heartbreak”

The series finale consists of two episodes Written by Russell T Davies and directed by Jamie Donoughue. The Legend of Ruby Sunday will stream on 15 June 2024 midnight, 00:00 BST (14 June 7:00pm ET) on BBC iPlayer in the UK and Ireland and Disney+ everywhere else, where available. The Legend of Ruby Sunday will also broadcast on BBC One in the UK on 15 June at 6:45pm. On 22 June, the final episode of the series, Empire of Death will stream on iPlayer and Disney+.