A person can come up with the perfect ideas, and doesn't mind if monsters come to him with those ideas. Predictably, the Doctor isn't impressed.

The concept of an “accidental idea thief”—someone who steals people’s plans and unwittingly returns them—is a really compelling one, and the story gets good mileage out of it. I enjoyed how the Doctor foils this plan and encourages the character to use their powers for good. Initially, the character is indifferent to the impact of their actions, not caring whether the consequences are positive or negative, which I found interesting.

I also liked the twist at the end. It seems the Doctor had planted the idea for the character’s eventual course of action in their mind at some point in the past, though I’m not entirely sure I fully understood the realisation the character has at the conclusion. Regardless, the journey was enjoyable, and it was clever to see the Doctor subtly disrupt and infiltrate this person’s life’s work.