A storyline could involve a character from Torchwood getting trapped in a time loop. The 11th Doctor shows up and, with his knowledge of time mechanics, tries to break the loop. Along the way, he gets to know the Torchwood team better and they learn a great deal from him about the nature of time and the wider universe.
Well, in this fanfiction, there could be a lot of exciting crossovers. Maybe the Torchwood team and the 11th Doctor team up to fight some new and powerful alien threats. They might share their different technologies and knowledge. For example, the Doctor's TARDIS could be used in a new way with Torchwood's high - tech equipment.
Well, there could be all sorts of adventures. Maybe they'd team up to fight a new alien threat that neither could handle alone. The Doctor's wacky and brilliant ideas combined with Torchwood's more grounded, Earth - based tactics could make for some really interesting scenarios.
One possible plotline is that they meet in a time - locked situation. They have to work together to break the time lock. Another could be that they meet because of a shared enemy that has somehow found a way to target both of their timelines. They would then have to put aside their differences and use their individual strengths to defeat the enemy.
The main characters would surely include the 11th Doctor. He would bring his TARDIS, sonic screwdriver and all his time - lord knowledge into the mix. From Torchwood, Toshiko Sato could be a significant character. Her expertise in technology and her rather shy yet intelligent personality could add depth to the story. She could potentially help the Doctor with some of his more complex technological problems, and in return, the Doctor could expose her to things she had only dreamed of in her scientific pursuits.
Another plotline could be that the immortal has some knowledge that the Doctor needs. The Doctor is constantly seeking knowledge, and the immortal, having lived for so long, might hold the key to solving a big problem in the universe. So the Doctor has to convince the immortal to share that knowledge, which might not be easy as the immortal could be very guarded about it.
One possible plot twist could be that they find out they are both parts of a larger plan by an unknown enemy. Maybe an ancient force has been manipulating their timelines to bring them together for some sinister purpose.
Perhaps they find themselves in a situation where they have to rescue a group of people trapped in a parallel universe. Jack's skills as a former Time Agent and the Doctor's ability to navigate difficult situations would be crucial in this rescue mission. It could also be a chance for them to learn more about each other's pasts and grow as characters.
In fanfiction, when the 13th Doctor meets the 11th Doctor, there could be a lot of chaos and fun. They might exchange stories about their adventures. Maybe they would team up to fight a common enemy that spans across their different timelines.
In fanfiction, when the 11th Doctor meets the 12th Doctor, there could be a clash of personalities at first. The 11th is so full of child - like wonder and the 12th is a bit more reserved. But then they might find common ground in their love for the TARDIS and for saving the universe. They could end up learning from each other. For example, the 11th Doctor might teach the 12th how to be more carefree sometimes, while the 12th Doctor could show the 11th how to be more strategic in dangerous situations.
The key elements could include interactions between the characters from both shows, maybe a shared adventure or a mission to save the universe. Storylines could involve time travel paradoxes or facing a common enemy.