A/N: I upped the challenge and I'm going back to make each one exactly 100 words! I'm also going to spell everything the American way because I'm American and can't spell Britishly, so I apologize, since Amy and Rory and River and Doctor Who and BBC are British...
Rory came home with a small envelope. "Who's that from?" Amy asked as soon as she saw him.
"Doesn't say," Rory replied.
Amy took the green envelope covered in international postage stamps. The only writing was neat cursive in black pen: "Rory and Amelia Williams". She tore it open and pulled out a card-sized piece of paper.
"It's blank," Rory said. Then, "No, hold on…" as writing appeared, as if by some invisible hand.
Hello Mother and Dad!
This seemed like the best way to keep in touch—easy, discreet, and basically no time residue!
Hope you're well.
xoxo River