Disclaimer: I own nothing but what is in my head.
This is my idea of what the first scene 12's tenure should be and it is written in script form. I will consider it canon until series 8 actually arrives.
Crash to the Past
(The TARDIS rocks and shakes as THE DOCTOR hangs onto the consol and CLARA grips the railing. The TARDIS gives a lurch flinging both around and makes a high-pitched screech.)
CLARA: Doctor, do something!
DOCTOR: I'm trying. (looks down at the consol with a slight grimace and pushes a button at random)
(The TARDIS gives an even more violent jerk making CLARA scream and THE DOCTOR almost lose his grip.)
DOCTOR: (pulling himself back up) Well, that obviously wasn't right.
CLARA: Doctor!
DOCTOR: Alright, alright everything will be fine (pulls a lever)
(The TARDIS shudders violently one last time before settling down with its normal grinding sound. The machine gives a choking sound and smoke billows from the consol.)
CLARA: (coughing) What happened?
DOCTOR: I think we've just landed. (collapses onto floor)
(Scene fades to an attic. An older woman sits on a chair with a young girl on her lap and a slightly older boy sitting on the floor in front of her.)
GIRL: And then what happened grandma?
GRANDMA: And then, grandpa and I came home. Oh, we were so happy to be back we ran up and down the streets and laughed ourselves silly.
BOY: But weren't you even a little bit sad.
GRANDMA: Oh, yes, a little bit. We'd miss our friends and adventures, but we soon found out there were plenty of adventures to be had right here at home.
BOY: Yes, but…
(A woman's voice calls the names Lucy and Brandon from downstairs.)
GRANDMA: Ah, it seems your mother's here. Why don't you two go pack up your schoolwork and I'll pack up some of our fresh cookies for you to take home.
GIRL: Yes, grandma (kisses her on the cheek and climbs off her lap)
(Both run out of the attic door quickly and their footsteps are heard descending the stairs. GRANDMA rises from her seat and stops for a moment before the sound of grinding gears fill the room. The woman pauses in shock before slowly turning around to see the TARDIS materialize. The door to the TARDIS opens and a coughing CLARA bursts out of the door struggling to drag the unconscious DOCTOR by his armpits. CLARA gives one big yank and tumbles to the ground outside of the TARDIS with the DOCTOR on top of her. The door to the TARDIS slams closed. CLARA shoves the DOCTOR to the side and jumps up.)
CLARA: (to the TARDIS) Well you're a fat lot of help! Goodness. (Spins away and, catching sight of GRANDMA, freezes. CLARA glances between the TARDIS, GRANDMA, and the DOCTOR) Uh…
(GRANDMA stares in awe at the TARDIS and walks up to it without sparing CLARA a glance. She runs a hand over the door and smiles slightly.)
GRANDMA: The TARDIS.
CLARA: (eyes wide) I'm sorry, what?
(GRANDMA looks at CLARA and then down at the DOCTOR)
GRANDMA: (yelling) Ian!
(Cue Doctor Who theme song as the opening title sequence rolls.)
A/N: If you didn't figure it out, GRANDMA is Barbara. I want it to happen because he never went back to see them in the TV show and it makes me sad. (Yes, I know her actor passed away, but Barbara would have changed in appearance if she was old enough to have grandkids. If they could get an actress that would do the character justice…)