DISCLAIMER: I don't own Torchwood and Doctor Who.
Jeff Huntig observed his target as he looked through binoculars into the sky. Jeff curiously turned his own binoculars in that direction. He saw a young, blonde girl hanging on a rope under the barrage balloon. He shook his head incredulously. These 21 century humans were so impossible. Instead of blending into the crowd they were doing everything to get attention on them. He knew from experience. He met a few 21 century humans in various times with the same results for them – death. Jeff shrugged, it wasn't his problem, and went back to observing the reason for his being in this forsaken time. He saw, that the man said something and left, probably to help the girl, if Huntig knew something about him. And he knew a lot. Not only because he had been following him for the past few days, but because they were working together for almost a year in Time Agency. Up until he was betrayed by him. Jack had promised to help him and then he showed up late, which ended in death of Jeff's family. And Jeff couldn't forgive him for this. Then Jack Harkness disappeared and with great difficulty Huntig managed to track him down here. He watched, as the man of his musings ran through the alleys of the city in the direction of the Big Ben, where Jeff knew he had a cloaked ship. Making a decision Huntig got to his feet, quickly gathering his equipment. He descended from the roof of the building he camped for tonight and took off in the same direction as Jack. It was time for revenge. Nearing his planned destination, he checked his weapons, wondering which one to use to kill Jack Harkness. He wanted his death to be slow and painful, but at the same time he knew, that he couldn't spend much time to enjoy the show or use a more advanced weapon that humans have in this time. As a Time Agent he should do his job and leave as fast as he could without a trace. Sighing, he settled for a simple knife and positioned himself. He tried to look like simple passer by, when Jack appeared in the line of his vision. He smiled, when the Captain was just a step away from him and lunged at him, plunging the knife in his chest with pure joy and satisfaction. Jack's eyes widened in shock, he stumbled backwards, chocking a painful breath and then dropped to the ground, dead. Jeff Huntig grinned, yanking his knife out and wiping it on the man's coat. He pocketed the weapon and walked away, whistling happily. Jack Harkness was dead and the world changed.
Rose Tyler died, falling down from the barrage balloon. The Doctor found her a few hours later and struck with grief and guilt he barely managed to solve the problem with zombie in gas masks. Then he left the Earth and never came back. Torchwood Three ended its existence in 2000, when the team was shoot by their leader, who committed suicide after killing all of them. The Battle of Canary Wharf took out most of the London, before the Cybermens were stopped. Ianto Jones died in Torchwood One. Toshiko Sato never left her cell in UNIT. Gwen Cooper was on night patrol, when she answered a call about disturbance in the bar. She went with Andy and she was killed by the blow from the bottle of scotch in the head from the furious, drunk and agitated Owen Harper. He was arrested and he hung himself in the cell. Face of Boe and his good deeds vanished from the charts of history.
"We should come back here more often," Donna said, finishing her piece of cake made by her mother.
"What for?" the Doctor complained. As usual he got beating from a mother of his companion. "We have the whole universe."
"Oh, stop it!" Donna rolled her eyes. "It was your fault anyway."
"It was not!" Doctor cried indignantly and unlocked the door to the TARDIS.
"Yeah, yeah, whatever," Donna waved her hand dismissively. The Doctor turned and glared at her from the door. "Okay, okay," she conceded. "Have it your way." The Time Lord smiled. In that moment TARDIS shook violently and whirred. Surprised Doctor lost his balance and landed on the floor in TARDIS. The doors slammed shut and the whirring got louder and more insistent.
"Doctor?" Donna called, knocking. "What's going on?"
"I don't know!" he shouted, jumping to his feet and running to the control panel. He switched and pulled this and that, but the ship didn't respond.
"Doctor!" Donna yelled. "Don't you dare to leave me here!"
"I can't stop this!" the Doctor yelled above the noise the TARDIS was making, when she was starting her journey through the time and space.
"Doctor!" he faintly heard the angry voice of his companion and then there was silence. The Time Lord frowned and started to run the scans and diagnostics. His jaw dropped at the readings.
"What?" he exclaimed incredulously.