We meet the three stories that will converge.

"The Doctor looked at them, pulled out his sonic screwdriver and began to scan them. He looked at them again and pronounced, 'Hello people who have met Harry Potter before. How may I help you?'"

Charlie laughed and closed the door. She turned to Fred who was surveying the mansion in front of them. It was an extremely large square building with a towering structure coming out of the middle. It was a beautiful building.

“What did the Doctor say this place was?” asked Charlie.

“Downton Abbey, home of Lord and Lady Grantham, our hosts,” answered Fred. “Do you know how we’re getting into this party?”

Suddenly, there was another noise, this time coming from inside the room.

“Sorry!” said the Doctor, pulling out a funky little widget. “It’s my thing that goes ding when there’s stuff!”

“You’re lucky I like you, Doctor Smith,” called Lord Grantham from across the table.

Lady Mary nodded. “Yes. He said that the substance he found was ‘morphic residue.’ According to him, ‘morphic residue’ is secreted when a creature changes shape or form.”

“The murderer’s an alien?” sighed Charlie.

Smiling slightly, Lady Mary nodded. “Of course it is. And it’s a shapeshifter.”

"We have an alien to catch! But first I need to make a phone call!"

The Doctor ducked around the corner, leaving everyone behind. They all stared blankly after him.

"He doesn't even have a phone," pointed out Charlie.

"And the house phone is that way," said Lady Mary, pointing in the opposite direction of where the Doctor had run off.

“So,” said Fred. “Do you have any ideas what this alien is?”

“I have some guesses,” said the Doctor. “Definitely a shapeshifter which narrows it down to a couple hundred species. But one that can duplicate human… Which leaves us with a couple dozen… Operating in this sector… a dozen or so… I would have to run some tests…”

“Why didn’t you do this while you were gone for five weeks?” asked Rose exasperatedly.

The Doctor sent her an affronted look as they exited the room. “That would’ve been rude to Thomas.”

"That has to be the Zygon. She's far too hideous to be the real Edith," said Lady Mary matter-offactly.

The four friends were staring at Lady Edith who was staring back at them from a couple of stairs down from them. It had been she making the loud noise beneath them a couple of minutes earlier.

"We can't forget those who defended the Abbey with their lives."

Lord Grantham turned his eyes down. "Yes. Barrow and the two sisters. Did we lose anyone else?"