A pretty generic story. You’ve heard this setup a million times before, but here it is again.

The Doctor and Steven have landed on an interesting spaceship called “Not-Home”, which is made out of an hollowed out asteroid. Within the ship is a giant natural world which is completely unaware of the spaceship and its inner workings. Among the people in this world, Steven and the Doctor meet Korra. A young woman who soon gets picked as a “chosen one” by the god of this world.

That’s a lot of words to say that this is a sacrifice story to a mysterious god. A concept that has been done to death even within this very show. You immediately know what to expect the moment she gets chosen. The people will rejoice, but something will feel wrong. She suddenly will have to be sacrificed and so on and so on. And this story follows that path like any others would. There’s no real subversion of the trope, other than the priests who know nothing about the process.

It clearly tries to go for more by hinting at a possible romance between Korra and Steven, and while given a bit of time, it doesn’t really land.

The same goes for the conflict between the Doctor and Steven. They discuss when interfering with time is justified and when they should just back away. I appreciate that the story tries to tackle interference in a future context, since other stories tend to ignore discussions around that ("The First Wave" comes to mind).

But the explanation we get here is still short and doesn’t clear anything up. It’s mostly there to set up a conflict and nothing more, which is a shame. In the end, the predictable conclusion is reached and our party moves on.

Helmstone is a story you’ve heard before, which isn’t a crime, but that makes it incredibly predictable. Nothing is really gained from listening to this story. No character moments, no new concepts and no new threats. It is filler. Harmless filler, but filler nonetheless. It lacks a life of its own.