The Robots: Volume Four

 was a full cast audio anthology released on 8 June 2021 by Big Finish Productions. It starred Nicola Walker as Liv Chenka, Claire Rushbrook as Tula Chenka, Robert Whitelock as Skellen, Jon Culshaw as Vash Sorkov, Pamela Salem as Lish Toos, David Collings as Ander Poul and Gregory de Polnay as D84 and introduced Sarah Lambie as Graff Kirran.

Publisher's summary
During the events of Doctor Who: Ravenous 2, Liv Chenka left the Doctor and the TARDIS behind. Just for one year. A year during which she would live on Kaldor, and get to know her sister Tula all over again.

But Kaldor is going through a period of tumultuous change. Technology is changing at an advanced rate - the robots are evolving, artificial intelligence is adapting, and with these changes so politics is altering too. Dangerously.

Can Liv and Tula make a difference during the most turbulent time in the world’s history?

4.1 Closed Loop by Guy Adams

Toos needs Poul’s help on a mission so sensitive she won’t even tell him where they’re going. Needing to escape from his demons, Poul agrees. But he finds more ghosts waiting for him at their destination.

Landing in the desert, Poul can’t help but be reminded of his time on Storm Mine 4... and soon he’s hearing familiar voices.

As he and Toos start to dig, they’re about to discover that some secrets can’t stay buried...

4.2 Off Grid by Sarah Grochala

When a Supervoc is found on the streets, claiming responsibility for a recent explosion, it’s clear to Liv and Tula that the Sons of Kaldor are attempting to frame robots for their murderous attacks. But where are they? And how to stop them?

As they try to smuggle the Supervoc out of the city, it’s clear that finding the enemy will be the least of their worries as tonight... the lights are going out.

4.3 The Janus Deception by Robert Whitelock

Tula is under investigation by the company - for fraud, industrial espionage and conspiracy. She knows she’s innocent... so who is impersonating her? And why?

Liv, meanwhile, is nearing the finishing line of her trail, a meeting with the survivors of Storm Mine 4, in person. But will that really be the end... or a new beginning?