I have two novels of time travel I'd like to work on now. One, I am.
In it, a jumper disconnects their 'signal' the immaterial part of themselves, and travels downtime dodging angels eager to escort him to Heaven, and connects up with someone in a previous year. If done properly, the jumper takes over completely, and the normal mind is mostly sedated.
An agent goes back in time several centuries, builds a jumper out of Radio Shack equipment (its a trope), and recruits a desperate father who has a dying child. The father can jump back thirty more years or so to the 70's, and keep a baby alive who will grow up to be a child prodigy, and solve the illness that is besetting the father's child.
Its an interesting question as to why the original time traveller does not do this himself. Perhaps their is a limit on how far you can safely jump, and the target era is thirty or so years too far.
Its also a more puzzling question as to how the uptimers know this child is going to grow up to be a child prodigy.
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The other idea is less fleshed out. I wrote a bit on it years and years ago. I now have a new beginning.
The beginning is a great walled city of the Middle Ages type that is besieged, and is losing the siege. All about, things are falling apart. Brigades of troops are routing at the first sign of the enemy. There's something sick in the culture of the great city.
The ruler of the city is beset by her advisor who begs her to at last admit she was wrong, to take the Sword and cast it backwards. The ruler, who is terribly stubborn, and full of the brilliance of her ideas is finally forced to admit that it did not work. And so she completes the ritual. But at the last second as the Sword of Time is about to fall backwards, she reaches out and grasps it as well. The aide gapes in dismay, and she and the sword are tossed backwards. Fortunately, she loses the sword in the swirling race of the timestream, or she'd just go ahead and redo all her old mistakes despite seeing how they did not work before.
The Sword falls to a field, and is found by Typical Farmboy with Dreams of Greatness. I think. In the earlier version it is sought as a quest by a young paladin.
In any case, the sword allows you to step outside of time, and watch the chain of events occur at whatever level of detail you wish. It allows you to intervene, but such interventions are rough on the user, and expose the user to danger since while the user does have a magic sword....1)He doesn't know how to use its full powers. 2)Other people are better at fighting and/or have basic magic swords of their own.
It becomes apparent to the user that manipulating things is the way to go rather than jumping in and swinging the sword blade everywhere. This is also true as he realizes the effect his creation of the Hero Out of Thin Air has on the culture which is probably not going to be totally good.
He starts manipulating people, guiding them to quest items and helping great heroes dodge nasty occurences that might cut their careers short. He's changed from Hero to Merlin.
In the process of this, he realizes that he can create heroes. All he has to do is guide potentialities to a max, and shut off the other possibilities. Make a man strong and quick, and bend the lines of potentiality in the time stream so that he cannot become a blacksmith or a farmer, but must become a Hero. In short, he can create Destiny.
And he has people who want him to create Destinies for them. They want to be the great Hero, the guy who knows what he is supposed to do. But he finds out that in so doing, he impoverishes the person. He takes away much of their freedom.
Eventually, he has to guide things to a successful conclusion, keep his Heroes from being too impoverished, and defeat the idiotic cultural innovations that his Nemesis, the Queen from the Future wants to recreate to make her imagined utopia.
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I think its clear that Book Two might be beyond my skill level at this time.