Molten Heart deserves credit for an innovative setting, original aliens and a move away from obvious tropes. The setting (for the most part) is the interior of the planet Adamantine where strange rock-people live amongst lava seas and crystalline wonders. The rock-people are under threat, and the story blends together a topical mix of industrial excess, nanotechnology and environmental concern, but never so much as to crowd out the storytelling. Author Una McCormack’s world is populated by a fascinating cast of characters (with names such as Basalt, Quartz and Onyx) as intrigued by their human visitors as the TARDIS crew is by them.

As the story unfolds there’s the obligatory amount of imprisonments and tunnel chases, along with deluded rulers, politics and intrigue, as well as a story of family and friendship. The TARDIS crew get separated into pairs allowing two sides of the action to be seen as well as a range of perspectives amongst the human crew, with Ryan’s observations of the Doctor and Graham and Yaz having to rely on their wits to survive multiple challenges.

Despite plenty of shenanigans with the plot, there is a sense in which various threats never seem dramatic enough. In giving the rock-people a range of motives and personalities, and avoiding the cliché of alien equals bad, there isn’t quite enough to trouble the reader as to who might live to see another day. The ending is perhaps a little too nice, though readers can make up their own minds on this point.

At under 200 pages Molten Heart feels a little too short, and perhaps there’s not quite enough happening, which is a shame as it’s a fabulously conceived story. Length aside it’s a great read, with plenty of originality.

DOCTOR WHO: MOLTEN HEART / AUTHOR: UNA McCORMACK / PUBLISHER: BBC BOOKS / RELEASE DATE: OUT NOW