The Zygons have come to claim the Earth, and this time they're playing the long game. For the Black Cadre have a plan, a plan that will take exactly one hundred years to come to fruition.  

From the streets of St Petersburg to the plains of Death Valley, the Zygon Century continues… 

The epic audio drama series Zygon Century returns in April with a second box set of full-cast audio dramas, titled Transformation. It comprises three brand-new episodes set across the sinister Black Cadre’s time on Earth, each continuing the story of one of the characters introduced in the first volume, Infiltration. 

The opening story takes us to the 1920s and catches up with the paranormal investigator Herbert Scott (voiced by Father Brown star Jonathan Rigby). Then, Vorvoren (The Play That Goes Wrong’s Charlie Russell), a Zygon previously held captive by humans, investigates a cult in California. And finally, secret agent Caldwell (Joshua Manning) has a new mission, which takes him to the Soviet Union. 

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 
1968: An Incident in Death Valley by Lauren Mooney & Stewart Pringle 
1974: The Caldwell Restitution by Ken Bentley

Producer Jonathan S Powell said: “Zygon Century is back - and the invasion’s gone international! After the success of Infiltration, Jonathan Barnes and I were keen to push ourselves further and show our band of Zygons on the offensive. In these three exciting new episodes, we’ll take you across the twentieth century, from Russia to Dublin to Death Valley, and reveal more of the Black Cadre’s simmering masterplan.  

“I’m immensely proud of Zygon Century. There are many more stories still to be told, and we hope you enjoy these next three.” 

Script editor and writer Jonathan Barnes added: “I was very keen to come back to our three main characters for the second box set. So we have Herbert Scott, the occult investigator, Vorvoren, the most sympathetic Zygon in the entire series, and Agent Caldwell.  

“Not all of these people will survive to the end of the series, and there’s going to be many unexpected developments in their stories going forwards.  Writing a Doctor Who spin-off without the Doctor let us dive into new corners of the universe, following characters whose paths are unwritten. It’s a chance to tell stories full of mystery and possibility. That’s exciting to work with.” 

Praise for the previous Zygon Century box set, Infiltration: 

“Brutal, brave, and beautiful, Miracle [of Pendour Cove] is what Big Finish – what science fiction – is for.”
Doctor Who Magazine 

“If you’re a Zygon fan, you won’t be disappointed in this start to their 50th anniversary … 4.5/5”
Who Review 

“Remarkably good – I’m very annoyed that it was this good and I’m now invested and I want more!”
Tin Dog Podcast 

“Top tier storytelling.”
Sci-Fi Pulse 

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.