In an alternate reality altered by time travel, a protagonist must outwit time-traveling mercenaries to use a hidden device and restore the original timeline, only to discover a twist that turns them into the antagonist in a new reality.
Protagonist: A time traveler trying to restore the original timeline; Antagonist: A group of time-traveling mercenaries hired to ensure that the altered reality remains intact.
The protagonist discovers a hidden time-traveling device that could potentially restore the original timeline, but must evade the antagonist's efforts to stop them from using it.
The protagonist successfully uses the time-traveling device to restore the original timeline, undoing the alterations made by the antagonists. The world returns to its true state, and the protagonist's mission is accomplished.
Twist: The time-traveling device turns out to have a hidden agenda of its own, and instead of restoring the original timeline, it creates a new reality where the protagonist is now the antagonist. The protagonist must now find a way to undo the unintended consequences of their actions and set things right once and for all.