Donna Noble is back home in London, catching up with her family and generally giving them all the gossip about her journeys. Her grandfather is especially overjoyed — he's discovered a new star and had it named after him. He takes the Tenth Doctor, as his special guest, to the naming ceremony. But the Doctor is suspicious about some of the other changes he can see in Earth's heavens. Particularly that bright star, right there. No, not that one, that one, there, on the left...