Once time travel became a reality, museums had access to articles from the past in a way that no one had ever thought possible. But collecting from those antiquities would require the utmost vigilance. The tiniest possibility that the collection might cause a paradox must be avoided. When an alarm indicates that a major paradox threatens to destroy the universe as we know it, only one person has even the slightest chance of repairing the damage. Even though she is retired, Sara Michaels answers the call. But if she is successful, what will she lose?