(A/N: So sorry I haven't updated, but between a hectic last week of school and coming down really sick last week, I haven't had a lot of time, no pun intended.)

I don't own: Marvel, Doctor Who

"Now explain to me, Doctor," said Rose, once they were back inside the TARDIS, out of sight, "who are they?"

"Well, Rose, the year is 2013, if I'm not mistaken."

"So, near future?"

"Right. Last year, the U. S. of A. got their own up-close-and-personal alien encounter -"

"Who? Slitheen? Daleks?"

"No, Chitauri. You've never seen one before. The United States government has this organization called S.H.I.E.L.D., that deals with...abnormal threats and issues. So S.H.I.E.L.D. called in these superhumans to fight the Chitauri when they attacked. Iron Man - also known as Tony Stark, inventor, genius, billionare, famous womanizer, who fights within a suit of superpowered armor he built himself. The Hulk - a.k.a. Bruce Banner, ex-scientist who got his powers from a lab experiment gone way wrong. Captain America - a.k.a Steven Rogers, a WWII soldier who got his power from a lab experiment gone right, well, before being literally frozen, sleeping for seventy years, and waking up a man out of time. Hawkeye and Black Widow, two famous spies whose names shall remain secret because they're spies. And Thor, who -"

"Whoa, whoa, hold up a second. Thor?"

"Yeah."

"Like, the god of thunder? The real, actual Thor? Or are you messing with me?"

"Rose, is anything I tell you ever a joke?"

"Well, no..."

"But yeah. So, let's go say hello!"

Rose and the Doctor stepped out of the TARDIS, where the Avengers were still standing. "Now, Mr. Doctor, mind explaining to us who you are?", said Steve. "I mean, obviously it's not every day a blue box crashes through your window."

"Ah...yes, sorry about the window. I'm the Doctor, this is Rose, and this box here" -he patted the side of the box "-is the TARDIS. My spaceship. Normally I wouldn't tell anyone that, but you - you're the Avengers! I'm sure you see this sort of thing every day, hm? I mean, what with Loki and the Chitauri and all..."

"Whoa, hold up," said Tony, "how do you know so much?"

"Well, I know about the Chitauri because I've been to their planet."

"What? Can you tell us about them, then?"

"Oh, sure! Bloody uncomfortable place, that planet. But first, let's have a look around, shall we?", he said, pushing his way right past the superhero team and into the next room. "Aha! Well I'll be. Look's like that time of year again, eh, Christmas! Huh," he added, "something bad always happens when I stop for Christmas. Ah!," he exclaimed, looking at the TV screen Steve and Bruce had been watching. "Star Wars! Another one of the great Earth masterpieces. The sequels didn't measure up, though."

The Avengers could see that whoever this Doctor was, he clearly wasn't going anywhere soon.

"So tell me, Mr Stark...", the Doctor said.

"Call me Tony."

"Thanks, great! Call me Doctor. Anyway, what were you working on in there? Suit?"

"Yeah. Mark...37? Or 9? I don't remember. Anyway, there's a problem with the firing system. You into fixing things?"

"Yeah, sometimes. Can I take a look?"

"Sure," said Tony, passing him the armored glove.

"Hold on...," said the Doctor, pulling out his sonic screwdriver. A minute later, the firing was fixed. "There you go!"

"Wha- How-" He looked at Clint. "I'm still not sure who this guy is, but I've got nothing against him!"

Meanwhile, the Doctor, who had been looking at the calendar that Tony had been marking off 'til Christmas, turned to Rose. "Rose, I think we might have a problem."