Once every night a single policeman patrols the length of West Wallaby street on his rounds. Tonight it is slightly misty, as revealed by the street lighting. It is a quiet area of town and he walks without concern. The street is silent, so the town hall clock striking two is clearly heard; he stops to check his watch: a fraction after 2am. Then all the street lights flicker and dim, just for two or three seconds, and return to normal; this has happened before – in fact on several nights in the last few weeks - so the good constable thinks little of it. As he continues on his way, the town hall clock sounds two; he shakes his head in silent bemusement, but his footsteps do not falter.

At breakfast, much later that morning, Wallace's mood is optimistic. "Shielding, lad, that's the problem: once we can narrow down the range we'll really have cracked it!"

Gromit nods in dumb agreement, he knew that a month ago and finally his master has got the message. Then he hears a noise at the front door and goes to collect the post.

"Oo! The electricity bill. I was hoping that wouldn't come for a while yet." Wallace fumbles with the envelope and finally opens it with his marmalade knife. "GOOD GRIEF, this can't be right, we can't have used THAT much! The meter reading must be wrong, that's what it is." While he slips out to check the meter, Gromit takes a look at the bill. His eyes widen at the astronomical figure: this is not good.

A deflated Wallace returns to the breakfast table and sits down again; his mood has flipped to near despair. After sitting silently for a while, ignoring his half-eaten toast, he again studies the bill and shakes his head sadly. A wild thought strikes him: "You haven't been leaving your room light on again have you, lad?"

Gromit looks to the ceiling, but he knows his master will not be in denial for long and gives a sad little shake of the head. "No," says Wallace, "It's the experiments, I know. The machine needs too much power. This bill will clean me out good and proper. We can't go on like this; we'll have to think of something."

For the rest of the day, it being Sunday, Wallace can be seen hunched over large sheets of paper, a really sharp pencil and trusty slide rule to hand. Every so often, and unasked, Gromit refills his tea mug and puts out more cheese and crackers on his plate. Later, Wallace goes searching for Gromit and finds him scratching his head. "Fleas again, old friend?" he asks sympathetically.

For answer Gromit shows him the book he is reading: "Relativity for Profit and Pleasure." Wallace flicks through it, "Ah, only general relativity, eh, Gromit. Not ready for the special stuff yet, lad?"

Gromit's face is a picture, but Wallace is already on his way to the front door. "Come on Gromit, walkies! All work and no play makes pooch a dull dog. We'll go to the park and find a nice stick for you to run after. How's that!"

Back from the park, Gromit feels a strong need to unwind, so he curls up with the novel he is currently reading, "The Time Traveller's Whippet."

That night is uneventful; however the intrepid inventors are not idle for long. Quite soon, early one morning, the beat constable again sees the lights dim and this time he feels a vibration through the soles of his boots. Then with a whine, a rumble and a rattle an early milk float goes past, the street lights return to normal, and he thinks nothing more of it.

The day after that, before dawn, he hears the faintest of whines and on the other side of the street a robot dog goes by. Robot dogs are not unknown in town: the lady in the wool shop has one she calls Preston. There is no law against it, and he continues his patrol. He has hardly turned the corner when the robot dog returns and resumes its position opposite number 62.

The morning after that, the constable walks past the police box on the corner of West Wallaby street and stops: he is sure, quite certain in fact, that there were no police boxes in this part of town. He walks round it, fails to open it and decides to mention it to his sergeant when he gets back to the station. Later that day a uniformed sergeant arrives on a bicycle and looks around, consults his notes, looks around again, sees no police box because there is none to be seen and leaves, deciding to speak to the inspector about a certain constable. Late that evening, the inspector, a most diligent officer, stops by in his car and takes a look around. Despite the dark he soon spots an old police box in the front garden of number 62. He briefly wonders whether to call at number 62, but decides it unnecessary and drives away. Minutes later Gromit hears a strange sound, switches on powerful security lights to flood the front garden with light and looks through the front windows, but there is nothing to see.

Later, in the small hours, Wallace and Gromit are setting up for another trial run of their machine, down in the cellar, when there is persistent ringing at the front door. "Oh Eck! I do hope it's not someone from the electricity," says Wallace nervously. "Gromit, turn the machine off, while I see who it is."

Wallace has had to pawn their CCTV and the cellar-to-door intercom is broken, so he climbs the cellar steps while the ringing continues. Gromit, sitting at the big control console, throws lots of switches; wavering needles go back to zero on their dials; the vibration in the air ceases; flashing lights go out and in the street the lamps become a little brighter.

Meanwhile, Wallace has drawn the bolts and unhooked the chains on the front door. Plucking up courage he takes a deep breath and flings open the door to reveal a man with masses of curly hair and an inane grin, wearing an improbably long, multicoloured scarf.

"Nice to meet you," he says, "you are Wallace, aren't you? This is K-9. Can we come in, we have a lot to talk about."

Wallace is taken aback, both by this beaming, rapid-talking stranger and the mechanical dog at his feet. "Um, talk? At this hour? Who are you?"

"What does the hour matter when you are a time traveller? What you are doing is more dangerous than you know. I am called The Doctor. Can we come in?"

Wallace is so gob-smacked, that the Doctor and his metal dog are in and the door shut behind them before he realises what is happening. Then Gromit comes up the cellar steps and finds himself nose-to-nose with K-9. He backs off slowly, greatly alarmed, keeping eye contact; he is a wary animal and the memory of the mal-functioning Preston is fresh in his mind.

"Come on K-9," prompts the Doctor, "introduce yourself."

"Yes master. I am K-9. How do you do, Gromit?"

Gromit has never encountered a talking robot dog before, and is perplexed as to how to respond, fear of physical danger replaced by a social dilemma: he does not talk and K-9 has no hand to shake. Should they rub noses? Or sniff bottoms? Surely not! Gromit settles for a nod of the head. For once, Wallace comes to Gromit's rescue: "Gromit is no great talker, but he is very bright, helps me with all my inventing."

"Yes," says the Doctor, "and that is why K-9 and I are here: you are trying to build a time machine."

"But … but how could you know that?" splutters Wallace.

"Because I am a time traveller myself. Now, are you going to show me your machine?" asks the Doctor, grinning and wide-eyed with enthusiasm.

"Are you sure you're not from the electric?" asks Wallace, still worried.

"Quite sure; do I look like an electrician?"

As K-9 is "not good with stairs," it does not go down to the cellar with Wallace and the Doctor. Gromit remains with it, not trusting these strangers at all. However, when Wallace and the Doctor eventually emerge from below they find the two dogs totally absorbed in a game of chess; Gromit is determined not to lose to a machine, but K-9 is a very strong player and Gromit is struggling to manage a draw.

"Gromit," says the Doctor, "this time machine of yours, it won't work you know."

"But it does work!" interjects Wallace, "Last week we sent Gromit's alarm clock back nearly ten minutes, didn't we lad?"

"Did you?" asks the Doctor, "and does it still work?"

"Ah … well … I've been busy lately, I'm sure I'll getting it ticking again in time."

Wallace becomes uncomfortable under the Doctor's silent stare. "It's still early days. Gromit, show the Doctor our equations."

Glad to escape from a match he is losing, Gromit wastes no time in dashing off to find his notes. The Doctor gets Wallace to sit down and tries to calm him. "Why did you decide to try time travel?"

"Well, it all started when I went to the public library to return some books which were due back. I was too late, it was closed for the day. One of the books was one Gromit had borrowed, "The Time Machine" by H.G. Woofs, and that got me thinking."

"You thought you could build a time machine?"

"Aye! If I could get one to work I would never have to pay a library fine again."

"Ah."

Gromit returns with a sheaf of papers thick with equations and workings out. Soon he and the Doctor have their heads together discussing Gromit's maths. Wallace hovers behind, well out of his depth. "Err, Doctor, would you care for a cup of tea, perhaps?"

"Three sugars please, I have a sweet tooth."

It is not long before the Doctor discovers the flaw in Gromit's work: "Gromit, your mathematics show real promise, but you've assumed this equation has only one solution, but it has several. Look!"

Soon Gromit is nodding in agreement; he has seen his mistake and agrees that they were lucky that their time machine did not cause a catastrophic explosion. To cheer up the pair of them, the Doctor invites them both to take a look around his time machine. "It is called a TARDIS: Time And Relative Dimensions In Space; and it is parked on your front lawn."

Gromit walks around it on all fours, looking puzzled and disbelieving. "Compact, isn't it," says Wallace. The Doctor says nothing, but opens the door and ushers them both inside. For a while they can only gawp, but soon Wallace is itching to get his hands on the controls, even as the Doctor is explaining the use of some of them. However, Wallace is also yawning and falling asleep on his feet, he has had a very long day. They manage to steer him back into the house and soon he is snoring away in his armchair.

The Doctor has a quiet word with Gromit, "Would you like to travel with me and K-9 for a while? The TARDIS can go anywhere and anywhen. I can show you the cosmos -Pluto and Sirius if you wish - taking as long as you like, and have you back here before he wakes up."

Gromit makes a pleading look, but the Doctor is firm: "I am very particular in the choice of my travelling companions and I do not choose your master. It is you alone, or neither of you. But he need never know, it isn't as though you were abandoning him."

Gromit shakes his head, but is clearly torn.

"Well, it's goodbye then, Gromit. Say goodbye to Wallace for me. Tell you what: I'll leave the TARDIS door open for two minutes."

Gromit walks slowly away, with several backward looks, goes into the house and closes the door. One minute later, though, he comes racing out, a tiny suitcase in hand, and darts through the TARDIS door just as it is about to close. "Welcome aboard," says K-9.

The TARDIS de-materializes and just minutes later re-appears on the lawn. The door opens and Gromit walks out empty handed, his suitcase long lost and forgotten. He looks around; dawn is rising and in the house Wallace is still snoring.

THE END

Author's Note: This story is a one-off and complete. I have no plans for any further stories on these lines. If you would like to write about Gromit and the 4th Doctor, then please go ahead.