Doctor Who: The Third Doctor Adventures — The Planet Killers is out today from Big Finish Productions — a 224-minute, two-story audio box set that pulls Tim Treloar’s Third Doctor from Siberian exile to the edge of planetary obliteration, with Katy Manning’s Jo Jones along for both journeys. A strictly limited collector’s edition CD run of just 1,500 copies makes this the scarcest physical format Big Finish has offered in 2026’s classic-era lineup.

The set pairs two stories with almost nothing in common except their leads. One reaches deep into Tsarist Russia for a historical horror mystery built around one of literature’s most famous physicians. The other sends the duo headlong into a Dalek extermination campaign on a world that never saw the threat coming. Together, they make a case for why the Third Doctor’s audio run remains one of the most tonally daring ranges in the Big Finish catalog.

The Reunion at the Center of It All

Tim Treloar stepped into the role of the Third Doctor for Big Finish in 2015, taking on a character that Jon Pertwee had defined on British television throughout the early 1970s. Katy Manning — who created Jo Grant during those same television years — has continued developing the character decades on, now working under the name Jo Jones following events depicted in later Doctor Who on-screen stories. Their on-audio chemistry across recent releases carries both stories here, even when the worlds around them couldn’t be further apart.

Producer Heather Challands described the pairing’s central appeal in Big Finish’s announcement: “We’re reuniting the Third Doctor with Jo Jones for this release, telling two stories that are very different from one another.”

Story One: Chekhov, a Census, and Something Howling in the Mines

The Beasts of Sakhalin Island, scripted by Jez Fielder across four episodes, anchors the box set in Imperial Russia. When the TARDIS deposits the Doctor and Jo on Sakhalin Island in 1890, they encounter the celebrated writer and physician Anton Chekhov — voiced by Joe Eyre — who is there documenting the lives of convicts held in the island’s notoriously brutal penal colony. The visit has a solid historical foundation: Chekhov really did make that arduous journey east across Siberia in 1890, conducting an extensive census of the colony’s population and returning with the research that would become his social documentary Sakhalin Island.

In the audio drama, what begins as a humanitarian chronicle takes a darker turn when an unexplained illness spreads through the colony and anguished sounds rise from somewhere deep beneath the earth. The production also features Sasha Alexandra and Bruce Alexander in guest roles.

Challands noted the pitch arrived with an element of surprise: “I was thrilled when this pitch came in and amazed that Anton Chekhov hadn’t already made his way into an episode.”

Story Two: A Beautiful Planet With a Dalek Demolition Order

The second entry, The Planet Killers by Andrew Smith, abandons history entirely. Directed by Barnaby Edwards, the two-part adventure drops the Doctor and Jo onto Paratel — a tranquil world already marked for total destruction. The Daleks, voiced as always by Nicholas Briggs, have orchestrated a scheme involving the forced extraction of Paratel’s mineral resources, mass enslavement of its people, and the planet’s outright demolition. As the pair work to dismantle the operation, the cost climbs steadily higher for everyone caught inside it.

Drama School Graduates Land Their First Credit Alongside the Daleks

The Planet Killers carries an additional layer that sets it apart from a standard Dalek adventure. Its entire guest cast consists of five graduating performers from Bristol Old Vic Theatre School — Emily Hurst, Peter Devlin, Tom Brace-Jenkins, Ellie Carnaby, and Kieran Devine — all of whom received full professional credits on the production.

The path to that casting began when the school approached Big Finish in mid-2025, asking whether the company could offer a masterclass for its acting students. Big Finish went considerably further. In May 2025, Barnaby Edwards and Nicholas Briggs ran a full-day workshop at Bristol’s Christchurch Studios — a venue with deep roots in Doctor Who audio history — and then selected five participants to perform in an actual production. All recording took place at the same location before the studio was decommissioned as part of local redevelopment.

Edwards explained the thinking behind the format: “I know how difficult it is to get that first professional credit, so this was a great way of opening doors into the industry.”

Challands echoed that sentiment, pointing to the leads’ role in making the arrangement work: “Not only are Tim and Katy wonderfully generous as leads, perfect for the graduates, but Barnaby Edwards was able to come on board to work with them and direct this episode.”

Pricing, Bundles, and the Physical Deadline

The full box set is available now at Big Finish for £19.99 (download only) or £24.99 for the download paired with the collector’s edition CD. That physical format is strictly limited to 1,500 units and will not be reprinted once the run sells through.

Listeners looking to pair this with February’s The Imposters — the first Third Doctor Adventures release of the year — can do so for £38 (download) or £47 (download plus both collector’s edition CDs). A larger bundle covering all 15 Classic Doctor Who box sets released in 2026 is available for £285 (download only). Every listed price is guaranteed through November 30, 2026.

Big Finish is currently running a digital-first release schedule, which means CD shipments may follow the October digital launch by some weeks. Every purchase, however, unlocks immediate download access through the Big Finish app.