I don't actually watch Dr. Who (though I am aware of vague snippets of plot thanks to my fangirl buddies), but heyyyyyy that doesn't actually impact my experience all that much, for which I am incredibly grateful! I'm going to go ahead and echo what everyone else is saying about characterization being great and the awesomeness that is Adam. Adam in particular intrigues me, because he's, you know, Adam. I think you're handling his character really well given how little we know about him—he seems to fit into the universe seamlessly.

One question, though: in the summary, didn't you mean that Adam receives a visit from an old friend? Unless you meant that Leonardo's logic comes up and says: "Hello, and by the way you're lost," and the Doctor's like FFFFFFFFFF

Anyway, I'm really intrigued to see what you do next!!