My first ever crossover story. I hope I got everything right. ^^;

Disclaimer: I do not own Ben 10 and Doctor Who. Ben 10 belongs to Cartoon Network and Doctor Who belongs to the BBC.

Genre: Humour/Sci Fi

Rating: T

Ben 10 and the Doctor

Prologue

Ben, Gwen and Grandpa Max were spending the night at a local park for their summer vacation. Ben was sitting on the bench with his Ominatrix, thinking about his first encounter with Kevin. Gwen was with Max by the campfire making marshmallows. It wasn't long before Max walked up to Ben for a strict chat about that night.

When they were in New York, Ben wanted the latest Sumo Slammers game, but got them kicked out of the hotel they were staying in for sneaking in. From there on, things got out of hand. He met Kevin who would later on become one of Ben's ultimate enemies, and his chase as Stinkfly caused a major stir with the press. All because of a video game he wanted. The next morning, Ben apologized, but Max knew it would take more than that to earn his trust back.

Ben, Gwen and Max were back in their van when Max started his chat with Ben.

'Look', said Max. 'About what happened in New York, it was not the right thing to do.'

'I know,' groaned Ben. 'I guess I just didn't know what I was getting myself into. Why do you feel the need to bring it back up?'

'Because I just felt that all this time during our summer vacation, whenever you do something dangerous, I get worried that you could make a mistake, and that mistake could be life threatening.'

'Since when did I ever get involved in any life threatening stuff?' He then noticed Max's look, reminding him of the incident. 'Look, I did apologize then. What more do you want?'

'For you to start learning, Ben. Sooner or later, you're going to learn that this alien business is not all fun and games. It can get dangerous if in the wrong hands, and I think you know how that went.'

He was right. When Kevin absorbed the powers of the Ominatrix, he became more dangerous than Ben ever could imagine.

'I think it's time you got some sleep.' Max called out Gwen as Ben headed back to the camper van.

Later, Ben and Gwen were ready for bed. Max was with Ben.

'Just remember: not all adventures are fun and games. It can be life threatening, no matter what you try to do.'

With that, Ben went to sleep.

Up in space, a giant spaceship was hovering over Earth. Vilgax, Ben's arch enemy, was still upset that he had not yet obtained the Ominatrix yet.

'That selfish little Earth brat will soon be destroyed, and the Ominatrix will be mine,' said Vilgax. 'But after failure after failure, I will not let this happen again.'

'So, how are you planning to stop him this time?' asked one of the robots.

'I have found help,' said Vilgax, with an evil smile. 'Someone who can lead us to their whereabouts, no matter where they are.' He then proceeded to open the door. It was pitch black inside…

…except for a blue light the size of a flashlight, and a robotic voice…

'EX-TER-MIN-ATE! EX-TER-MIN-ATE! EX-TER-MIN-ATE!'

Chapter 1

Ben woke up to a whooshing sound outside the 'Rustbucket', followed by a clunk. 'Rustbucket' is the nickname Ben gave the camper van. He then saw Gwen and Max wake up as well.

'What was that?' asked Ben.

'I don't know,' said Max, 'but whatever it is shouldn't be up at this time of night.'

They all got out of their beds and walked out. As soon as they did, they stopped. Max gasped, while Ben and Gwen looked in amazement. In front of them was a blue British phone box.

'How did that get here?' wondered Gwen.

'I don't know,' said Ben, tuning up his Ominatrix, 'but it's about to meet its match.'

Max stopped Ben. 'No. I think I have a feeling that I know who this might be.'

It was true. Max was a Plummer, a soldier who fought aliens in order to keep peace, so he knew most of the alien races. Suddenly, the door opened. They looked to see a young man in a long trench coat walking out of the phone box. He then started looking around, until he saw Ben, Gwen and Max. He walked towards them.

'Hello,' said the man. 'You must be Max.'

'I'm very surprised to meet one of you,' said Max. 'These are my grandsons, Gwen and Ben.'

The man kneeled down. 'Wow,' said the man to Gwen, 'you're quite easy on the eyes.'

Gwen blushed. 'Please, you're not too bad yourself.'

The man then turned to Ben. 'And you must be Ben, the kid with the alien watch.'

Ben was surprised. 'Hey, how did you know about the Ominatrix? Wait, before I ask that, who are you?'

'I'm the Doctor.'

This made Ben more confused. 'Doctor who?'

'He's a Time Lord, Ben,' said Max. 'A race of aliens who travel in time to try and set things right.'

'Indeed,' said the Doctor. 'I've been sent here to be with you three because someone is trying to get to your alien device there.' He then pulled out a picture. 'Recognize this?'

'Vilgax,' said Ben, almost immediately. 'What does he want this time?'

'The usual: your watch. Only he's found himself a helping hand, and you three alone won't be tough enough to take it down.'

'It?' said Ben. 'We're dealing with a robot?'

'Not just any robot, Ben,' said the Doctor. 'I have a bad feeling that I may know it too well. Well, let's not waste any more time. If you want to battle Vilgax, you'll have to come with me.'

He then snapped his fingers and the door of the police box opened. Gwen was impressed.

'Cool,' said Gwen in amazement.

'Oh, that reminds me. I could do with a temporary companion. How about you, Gwen?'

Gwen blushed even more. 'Sure. I'd love to.'

'He's quite the ladies man, isn't he?' said Ben to Max.

'It's definitely something to get used to,' said Max.

The Doctor then led Ben, Gwen and Max inside the police box. When they walked in, Ben and Gwen were in amazement. It was bigger than they thought. Of course, Ben was the one who discovered the fridge logic of the box.

'How come something this big fits into that small police box?'

'That's technology for you,' said Gwen.

'Now then, this is the Time and Relative Dimensions In Space, or TARDIS for short. It's my mode of transportation for traveling through time.' The Doctor was dialing all sorts of things while Ben, Gwen and Max were walking around the TARDIS.

'Right, we're all set to go,' said the Doctor. 'I'd advice you to sit down or hold on to something, especially you Gwen, because the start can get a bit bumpy.'

Gwen and Max then sat down onto chairs that were nearby. Ben on the other hand was still walking around, amazed by the technology. Of course, Gwen knew what was about to happen, but she didn't tell him.

'Allons-y!'

The Doctor pulled a lever, and the TARDIS was in motion. It jerked around a bit, causing Ben to fall to the ground.

'I told you to hang on to something.'

Gwen couldn't help but giggle.

'Very funny, Gwen,' said Ben, sarcastically. He made his way to the chairs and sat onto the railing. Although Ben was a bit unsure about the Doctor and what he was doing, he would soon get used to his antics.