A little girl who lives on the moon with her parents goes out for a walk. She ends up getting recruited to save galaxy. Once she's done, she is returned home through time travel and is shown to have been gone for only 5 minutes.
A little girl lives with her parents on the moon, goes out for a walk and ends up on an adventure saving the galaxy
Welcome to Science Fiction & Fantasy! This question would be improved by going through the checklists here ; How to ask a good story-ID question?– ValorumMay 21, 2018 at 23:24
possibly the same as scifi.stackexchange.com/questions/194642/… (which is newer but has an accepted answer)– OtisSep 14, 2018 at 1:30
The plot is vaguely similar to Heinlein's Have Spacesuit, Will Travel. The little girl is a secondary protagonist, but some of the action happens on the Moon and Pluto, and the protagonists do save, not the galaxy, but the human race. And in the end they are returned after weeks of adventures to a time shortly after they left, to their surprise. "Return them forthwith, to the space/time from whence they came."