Author's note: I own nothing but Bella and her backstory. If I did, I would be one happy camper, however.
The Doctor had parked his Tardis in orbit around the Earth while he showered and changed after leaving Donna with her family. Part of him wanted to set the course to random, to run as far away from there as he could but there was still a chance that the test on the Dalek crucible had caused some rifts to form. He had programmed the Tardis to scan for anomalies while he cleaned up.
He was debating whether or not to take a short nap when the Tardis alerted him to a discovery. A small rift had formed in an alleyway in London. It had promptly closed but some residue remained in the area. Oddly enough, the residue was similar to that of a Tardis.
Surprised, the Doctor immediately set the coordinates for the alley in question. The alley was empty when he arrived but his sonic picked up some definite Artron readings, identical to that a Tardis would leave in its wake. The Doctor looked around for signs that an actual Tardis had parked there in the recent past. He found a small dark pool on the ground near the trash bins. Upon examining it, he realized with a start that it was blood.
Time Lord blood.
The Doctor quickly switched settings on his sonic to search for any Time Lords in the area. The signal was weak but it was enough to send him running. He dodged around the revelers celebrating the fact that the Earth had been restored to its proper place as he tried to lock onto the signal. Whoever it was could be a threat and they needed to be stopped. After the Crucible he was not in the mood to play games.
He skidded to a stop when he encountered a large crowd of humans blocking his way. He was close, really close, and these humans were in danger. He needed to see what he was facing and fast so he climbed atop a nearby statue and looked around.
A woman near the center of the crowd caught his attention. Her right arm appeared to be bent at an odd angle and she was turning circles like she was searching for something. He aimed his sonic at her and confirmed that she was his target.