Let the good times roll

A story idea that's been floating around in my head for several months:

The Grandfather Paradox

The military of a superpower develop an experimental time machine. They can send a small team (3 or 4 soldiers) back, and return them. They reason that they can win battles that have already been lost, or send spies back in time to gather information about enemies who were not known then to be dangerous.

There are, of course, objections from scientists. Time travel makes paradoxes possible. Also, minute events in the past could be accidentally changed, leading to unforseen changes in the present. All these objections are overridden.

As an experiement, a team is sent back one week. They keep themselves inconspicuous, doing little more than take up space and breathe air that they didn't do the 'first' time the week happened. They are returned, with no apparant ill effects, no paradoxes, and the only changes to the presents are those defined by the experiment.

Another team is selected, and, feeling more confident and adventurous, they go back a whole century. And promptly cause the death of one of their grandfathers. In shock, they return to the present, to find it unchanged. The soldier who's grandfather was killed, and who's father never existed, still exists.

But anomalies start to turn up in people's memories, and in historical records. There are two timelines, simultainiously existing, but one one track instead of side by side. One has the grandfather, the other doesn't. As time progresses in the present, it is progressing at the same rate one century in the past, and the grandfatherless history is erasing the original one at a rate of one second per second.

The 'new' timeline will never catch up with the 'old' one, but the past is being continually rewritten.

Another team is sent back to try to prevent the death. They botch the job, and a third timeline is introduced, erasing the each moment of the second, soon after the second erased each moment of the first.

A fourth team goes back 20 years, intending to set the past right by introducing a substitute grandfather for the one lost by the soldier. The soldier now finds his memories of 21 years previous show him with one grandfather, but those of 19 years ago show him with another. And each day his memories change.

A fifth team is sent back to sabotage the time experiments, in the hope of 'resetting' the present. They succeed in the sabotage, but those in the present find they are living with the effect of time travel, while remembering the failure of the time travel experiments, and still possessing the technology, which now was never developed.

Panicking, dozens more teams are sent into the past. Some return and some don't. Some are killed by teams sent to undo what they did, others are then unkilled when their killers are retroactively killed. The past becomes a mass of conflicting histories, each being constantly rewritten and restored by each other.

As the story ends, each person's memories, their lives, even their existences are subject to constant and unpredicatable change. And more and more expeditions are being sent out to fix it.