The Black Cadre, a group of Zygons with a sinister scheme to infiltrate and take over Earth, will return in April 2026, with three brand-new audio episodes set across their hundred-year occupation. But two notable Doctor Who guest stars will be standing in their way. 

In the second episode of Zygon Century: Transformation Vorvoren (Charlie Russell), a Zygon who’s escaped her human captors, travels to Death Valley, California, where she has a tense encounter with the Master (Eric Roberts). 

And the box set’s third episode is a spy-fi spectacular, as the British agent Caldwell (Joshua Manning) teams up with the Third Doctor (Tim Treloar) for a 1970s-set espionage operation behind the Iron Curtain. 

The Worlds of Doctor Who – Zygon Century: Transformation is available to pre-order now for just £19.99 (download to own) or £29.99 (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 1,000 copies and will not be re-pressed.   

The three new stories in the Zygon Century saga are: 

1922: The Black Cadre by Jonathan Barnes 

From Munich to Dublin to an asylum in Dartmoor, the Zygons have agents everywhere, and their plans are growing in scope and ambition. 

Can Herbert Scott, that long incarcerated investigator of the occult, do anything to stop them? Is his rescuer – the German heiress, Ilse Lange – all that she seems? And why are the Black Cadre so interested in a mysterious carnival, travelling the wilder reaches of the Cornish coast? 

1968: An Incident in Death Valley by Lauren Mooney & Stewart Pringle

Fleeing her brutal human captors, and in hiding from the Black Cadre, the Zygon Vorvoren arrives at a run-down diner in the bowels of Death Valley. There, she finds a friend in Junie, a young waitress, and a town terrorised by a ruthless cult. 

But just who is their mysterious leader, ‘The Arkon’? And could he really hold the key to Vorvoren’s liberation and revenge? 

1974: The Caldwell Restitution by Ken Bentley 

Agent Caldwell has been posted to the British Embassy in Moscow and ordered to investigate a rising star of the Communist Party. But Caldwell is a shadow of his former self, plagued by nightmares of the past and misty visions of the future. 

As the Third Doctor enters the fray, human and Zygon plots collide, and Caldwell’s visions threaten to endanger the world. Though neither man can remember the other, can the Doctor and Caldwell put a stop to the Zygon Century, once and for all? 

The cast of Zygon Century: Transformation also includes Jonathan Rigby (Father Brown) as the paranormal investigator Herbert Scott, James Swanton (Inside No. 9) as Anthony Poole, and Abigail Thaw (Endeavour) as Zanna and Shishkin, along with further names yet to be announced. 

Producer Jonathan S Powell said: “This time around we’re welcoming not one but two iconic Doctor Who characters into the Zygon Century fold. But what does the Master want with the Black Cadre? And what on earth is the Third Doctor doing in Soviet Russia? Schemes are unravelling, destines are converging, and all roads lead to world’s end. But is humanity ready?” 

The Worlds of Doctor Who – Zygon Century: Transformation is available to pre-order now for just £19.99 (download to own) or £29.99 (download to own + collector’s edition 3-disc CD box set). 

All the above prices (including pre-order and multibuy bundle discounts) are fixed for a limited time only and guaranteed no later than 31 May 2026. 

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.