A HP sequel based on 'The Four Clever Brothers' from Grimm's Fairy Tales. Entry for "Writers Anonymous Fandom Fairy Tale Rewrite Challenge". There are a couple of hidden allusions to two other pieces of writing, unrelated, in the text. Sharp-eyed readers may spot one, but are unlikely to spot the other...

Mike, a young astronaut exploring an abandoned alien base on the Moon, has accidentally set off a time machine which has transported him far back into the past, only to be captured by the very aliens who built the base in the first place. What will they do to him? And will he change history to bring his brother back to life? (sequel to a short story by Larry Niven)