A/N: This is an extended AU in which the Tenth Doctor doesn't regenerate, and Donna continues to travel with him; so just forget Turn Left/The Stolen Earth/Journey's End, as well as the specials and The End of Time. I've wanted to do something like this for quite a while. Written as a challenge between Shivver and myself because we were wondering how different it would be if Ten instead of Eleven had been at the opening of the Pandorica. Go and check out her take on it, with the Fifth Doctor!

By the way, this is part of my 'Doctor/Donna ONLY' collection of stories, featuring just the Tenth Doctor and Donna as best friends. Check out my community for more great stories with just the Doctor and Donna :)

PROLOGUE

"Doctor!" She comes running into the Tardis, breathless.

He looks up from working on the console, mallet in hand. He grins. "Did you have a … Donna, what's wrong?"

"There's a crack in the wall of my granddad's bedroom and …"

"Well patch it up then!"

She gives him her frostiest glare and he shuts his mouth, watching her carefully.

"He said he's been hearing noises through it, so I listened, and I could hear them too! It sounds like they're saying something about someone escaping!"

"Oooh," says the Doctor, his expression changing to one of interest. "Let's check it out then, shall we?"

XXXXXXXXX

Starship UK goes on its way, and the Doctor opens the Tardis door.

"Where to next?" he asks.

"Doctor, what's that?" Donna points in alarm, and he turns around to see a crack, glowing golden around the edges. "I thought you closed that crack up! What's that crack doing on Starship UK?"

"I … I sort of … glued it together. Glue doesn't hold forever, and we still don't know what caused the crack. Whatever caused it is still causing it. We need to find the source. Come on!"

XXXXXXXXX

"Before you go," Churchill interrupts, chewing his cigar. "Can you advise me on one other, small matter?"

The Doctor half rolls his eyes, and Donna turns away to hide a grin. They follow the prime minister to Bracewell's lab. The scientist is nowhere to be seen, but Churchill does not hesitate. He leads them to a small room, filled with odds and ends of machinery and tools, and nods toward the ceiling. Donna doesn't even have to look to know what it is: the crack in her granddad's wall.

"I'm trying to find out what it is," the Doctor is saying. "It's some sort of … rupture. A tear in time and space. We've seen it before. Just … just stay away from it, all right?"

"Well, thank you, Doctor. You've been a wonderful help." Churchill sticks out his hand and shakes the Doctor's vigorously, then blows a small kiss in Donna's direction. "Thank you, both of you."

"Any time," says Donna, saluting.

XXXXXXXXX

"Poor Vincent," murmurs the Doctor.

Donna's eyes fill with tears, and she turns away from the painting. "I was so sure!" she says. "I thought that we had given him a reason to keep painting … to keep hoping for the best."

"I guess it was too late by then. Still! You got your name on one of his paintings. He remembered how kind you were to him, and that's something. He didn't die as sad a death as he might have otherwise."

"I know. It's just … couldn't we go back? Couldn't we get to him years before he started going downhill?"

"I'm sorry, Donna, but no."

She sighs. "I knew you were going to say that."

They reach the Tardis, and the Doctor opens the door. Unnoticed behind them, the crack opens just a little wider.

XXXXXXXXX

"Oh, Gramps, you were marvelous!" Donna grins at him, then at the Doctor. "I'm so glad we got it all sorted out with the Silurians. You're really a member of the team now."

She looks back at the Doctor; he is staring at the crack, the same crack that has been pursuing them for so long. It is in the wall of the cave, and is much wider than she has seen it before. Hints of whispering float out of it.

"What is it?" asks Donna. "Why do we keep seeing it?"
"I don't know," he mutters. "Why does everyone seem to know but me?"
"I don't know," offers Wilf.

The Doctor pulls off his tie and wraps it several times around his hand. "Maybe there's something in there that will give us some information."
"You're nuts!" Donna says. "You can't stick your hand in there!"

"Watch me." The Doctor kneels down by the crack.

"Stop him, Gramps!"

"Uh, Doctor, I don't think ..."

The Doctor puts his hand in. His face contorts and he yells with pain. Donna springs forward, but he pulls his hand out before she can reach him. "Got it!"
"What is it?"

"It could be anything. Blimey, that hurt!" He opens his hand and is about to examine the thing in his hand when there is a sound behind them. All three turn and see Restac, crawling towards them slowly and painfully, her gun aimed right at the Doctor.

"No!" Donna and Wilf shout at the same time. "Doctor!"

"For my sister," whispers Restac.

Wilf shoves the Doctor aside just as the Silurian discharges the gun. The blast hits him in the chest, and he crumples to the ground.

Donna stares in horror, paying no attention to Restac as she breathes out her last breath: "Apes."

The Doctor is cradling Wilf's head in his arms. "I'm sorry, Wilf. I'm so, so sorry. That was my fault. I should have been paying more attention. Why did you do it, Wilf?"

"Because … you're the most wonderful man … I've ever met …" the old man gasps. "I don't want you to die."

Donna kneels beside her grandfather with tears streaming down her cheeks. "Gramps, you're gonna be all right. All we have to do is get him to the Tardis, right Doctor?"

The Doctor stares at her with that look that she hates so much, the one that tells her he won't answer because he doesn't have the heart to break her heart with words.

"Doctor, don't do this to me! You never give up! Help him. Please, Doctor."

His eyes remain fixed on her face, and he does not reply, but he begins to lift Wilfred up. Donna stands and is about to help him when she notices tendrils of light reaching out from the crack and surrounding Wilf and the Doctor.

"Doctor!" she cries.

He looks down and his eyes widen. "Get back, Donna!"

"What about you?"

"I'll be fine. Stay back. Get into the Tardis." He tosses her the key. "Come on, Wilf. Stay with us. You don't deserve to be erased."

But it is too late. Already the old man's form is growing translucent; the light obscures his face. The Doctor steps back and bumps into Donna.

"I thought I told you to get inside," he growls.

"We can't just leave him," whispers Donna. "You said that if he goes into the crack, we'll forget all about him. I can't forget him!"

"I'm sorry, Donna." He doesn't meet her eyes, but holds out his hand. "The key. I need the key."

She gives it to him, and he opens the door. "Come on, Donna, we need to go."

When she doesn't move, he takes her shoulders and gently leads her inside. "Donna, if you remember him, you won't forget him. Try to remember. Where did he live?"

"Chiswick."

"Brilliant. What was his full name?"

"Wilfred … Samuel … Mott. Mott."

"What did he always call you?"

She presses her hand to her forehead. "I don't know! I can't remember!"

"He called you sweetheart. Come on, Donna, don't give up!"

Slowly, her face clears and she looks up at him. The sorrow and pain in her eyes is gone, replaced by a slight look of puzzlement. "Is everything all right, Doctor?"

He turns away to the console with a sigh. "Molto bene," he replies, in a tone that says the exact opposite. Donna goes to his side.

"No, really. Are you OK? Because you look sad."

"What about you?" He turns and looks at her, and in doing so sees a picture frame lying face down on the floor.

"Oh, don't worry about me," she says. "Where do we go next?"

When she isn't looking, the Doctor picks up the picture frame. He turns it over, and sees a photograph of Wilf, Donna, and the Doctor on Felspoon. Wilfred, strangely, isn't fading out of the picture. The Doctor puts it in his coat pocket and sighs again.

A/N - I know that in the show, they meet Vincent after the Silurians, but I changed it because the Silurian one seemed like the best one to end the prologue with.