Continuing the First Doctor’s unbound journey, the second story in the series sees The Monk’s TARDIS circuit take the team off course to the site of a previous adventure, the planet Marinus. A lot has changed in the hundred years since they last dropped in. The TARDIS team have become national heroes, the Voord have become a peaceful race, and the Daleks are now masters of Millenius!

The TARDIS has brought the Doctor and his companions back to the planet Marinus, one century after their previous visit. They are greeted as returning heroes, figures of legend. But something is amiss in the city of Millenius. Everybody lives in peace and harmony…whether they like it or not.

The explanation is obvious. Somebody has reactivated the Conscience Machine and is set on removing free will from Marinus. Somebody – or some old enemies of the Doctor…

Big Finish Synopsis

Return to Marinus is an interesting sequel, not just to the opening in the Unbound series, but also to its TV predecessor, The Keys of Marinus. Morris’s pitch for the story takes it in a bold direction, as he morphs what is seemingly an ordinary adventure into almost an Avengers: Endgame-style team-up.

Now, before any of you walk away from this story thinking it might be a bit too bonkers of a concept to work, it does strangely manage to pull itself together by the end. The reason for this is pretty simple: Morris manages to keep the plot from overcomplicating itself.

Once the Daleks arrive on the scene, the plot basically boils down to one epic quest across Marinus to stop them. This affords the story numerous advantages. The most notable of these is Marinus’ worldbuilding. Marinus is a completely alien world filled with a host of different ecosystems. From its volcano filled with sentient lava creatures to its deserts with lakes of pure silica, their exploration throughout gives the planet a sense of scale which isn’t possible in more insular stories.

The long journeys across the planet also aid in creating moments for characterisation, or more aptly, the ever-evolving characterisation of the Voord. In the hundred years that have passed since their last visit, the Voord have had a significant change in their motivations. Under their new leadership, the Voord are no longer content with war and endless fighting, and instead, seek peace and want to help protect the world of Marinus. Their alliance ultimately plays a key role in stopping The Daleks.

Beyond the quest, there’s also a spectacular climactic twist. It involves a Dalek bait and switch, which Morris does well throughout the story to keep it under wraps. On reflection, the clues are all there, just tantalisingly out of reach.

While listening through, however, there is one glaring issue with this story: it comes with a prerequisite. Anybody wishing to engage with this story needs to have watched The Keys of Marinus. This advice is not only aimed at new fans but also at those who haven’t watched the story recently as well.  There are so many references, characters and actions that tie into both stories that you’ll lose some enjoyment if you don’t.