The Fourth Doctor (Tom Baker) is travelling with warrior woman Leela (Louise Jameson) and loyal droid K9 (John Leeson) in his three latest hour-long adventures in time and space. 

The brand-new box set The Ruins of Kaerula begins with a pair of linked tales set on the planet Kaerula. At two very different points in the world’s history, the TARDIS crew must broker a difficult peace, face a deadly threat caused by an experiment gone awry, and deal with the consequences of their own meddling in time. 

Then, the Brigadier (Jon Culshaw) joins the trio for the set’s third episode, which marks the fan-favourite character’s first appearance in The Fourth Doctor Adventures. With the Doctor’s old friend in tow, this adventure takes the TARDIS from Geneva to Jupiter. 

Doctor Who – The Fourth Doctor Adventures: The Ruins of Kaerula is now available to purchase for £19.99 (download to own) or £24.99 (download to own + collector’s edition 3-disc CD box set), exclusively here. Please note: the collector’s edition CD box set is strictly limited to 1,500 copies and will not be repressed. 

The fabulous Fourth Doctor’s three new adventures are: 

The Remains of Kaerula by Phil Mulryne

When a time anomaly brings the TARDIS down on the planet Kaerula, the Doctor and his companions set out to investigate. They soon meet two escapees from a nearby containment camp, who warn them of mysterious cave creatures. 

While Leela and K9 venture deep into the caves, the Doctor must broker a peace between the Kaerulans and the Rems... but on this occasion, time may not be on his side. 

The Ruins of Kaerula by Phil Mulryne 

The TARDIS crew have attempted to depart Kaerula, only for an experiment gone awry to drag them back to an earlier point in the world’s history. 

Now stranded, the Doctor, Leela and K9 encounter very different versions of people they’d only just met, and must deal with the consequences of their own actions. And the experiment has brought something else to this planet – something terrifying and deadly. 

Cry of the Banshee by Tim Foley 

The Brigadier uses the Time-Space Telegraph to summon the TARDIS to a stormy Geneva, where a World Peace Conference has been interrupted by a mysterious death. The Irish delegate has died of fright... after seemingly being visited by a Banshee. 

Tracing the source of the attack, the Doctor takes the Brigadier, Leela and K9 to a thirtieth-century space station orbiting Jupiter, with a boggy marsh for an interior. Deep within the station lie the answers to the puzzle… as well as secrets and dangers best left undiscovered. 

The box set’s guest cast includes Jonathan Carley, Rakie Ayola, Barnaby Kay, Anna Leong Brophy, Robyn Addison, Andrew James Spooner, Zora Bishop, Aaron Neil, Delroy Atkinson, and Reece Pantry. 

Lead actor Louise Jameson described the opening episode: “I love this script. It's beautifully crafted, it works on the grand and on the minutiae. We’ve got the us and them of society, but we’ve also got the triangle of K9, the Doctor and Leela, maintaining their personalities very clearly throughout the adventures. And there’s several cliffhangers – you’re left holding your breath at least five times!” 

John Leeson, voice of K9, added: “It’s a very environmentally based script and it shows us ourselves, because the world is pulling itself apart around us, more than it ever has before. And the way that science fiction treats it is to put it on a plane where it can be seen at a distance and recognised for what it is, in rather a dramatic fashion. 

“In terms of the part K9 is playing in this storyline, it’s simple devotion to duties as defender and protector of the Doctor, as a scientific advisor. It’s been tremendous for me over the years to have played this character, because he’s been everywhere and done pretty well everything. A Time Lord’s best friend!” 

This is the third of 2025’s Fourth Doctor Adventures box sets, after March’s The Hellwood Inheritance, and a third volume (Title TBC), due in September. All three can be pre-ordered together in a bundle from just £57 (download to own) or £70.50 (download to own + collector’s edition CD). All the above prices include the special pre-order discount and are subject to change after general release. 

Alternatively, listeners can buy this series as part of a bundle of all 15 Classic Doctor Who box sets released in 2025 from just £275 (download to own) or £335 (download to own + collector’s edition CD box set). Please note: the above multi-buy bundle pre-order prices are discounted for 2024 only and guaranteed no later than 31 January 2025. 

Please note that Big Finish is currently operating a digital-first release schedule. The mail-out of collector’s edition CDs may be delayed due to factors beyond our control, but all purchases of this release unlock a digital copy that can be immediately downloaded or played on the Big Finish app from the release date.