Chapter I:
"Hey Doctor" said Clara as she walked into the Console Room. "You know, it's my birthday today..." she said.
"It's your birthday?" the Doctor asked, suddenly standing up straight. "Clara, I have got a great idea!"
In Rose's and John's House, in a parallel universe
"Hey, John, we got a letter." Rose said, opening the Tardis blue envelope. "It's an invitation," she announced "from the Doctor."
In the Pond's house, in the 1940s, New York
"Dear Amy and Rory," Amy read out loud "you are invited to the Tardis for the birthday of Clara Oswald. I will pick you up in London, at 7 p.m, on Monday the 21st of January. Don't be late (not that that's important anyway).
–The Doctor"
"The 21st of January? But that's tomorrow." Rory said.
In the Jones' house
"Mickey?" Martha called. "Guess who we just got an invitation from?"
"Um, your mom?" Mickey guessed.
In River Song's cell
"You got a letter." said the guard, as he tossed it to her.
"Tardis blue, eh?" she said, smiling, as she opened the envelope and read it. When she was done, she turned around and announced "I'm really sorry." as she applied her hallucinogenic lipstick.
In the Tardis, one regeneration earlier.
"Doctor, do you usually get letters?" Donna asked.
"Um, no." said the Tenth Doctor.
"Well you got one now."
In the Tardis, another regeneration earlier.
"Ah, Rose is at home for the weekend. I got you all to myself, Tardis." the Ninth Doctor said.
"You got mail" the Tardis announced.
"Huh?"