Suspicious after the Cerritos docks for its second baryon sweep in the same year, Mariner sneaks into a command meeting. There, the Department of Temporal Investigations tasks the crew with finding a time traveler who is rewriting Federation history at an alarming rate. Mariner finds her friends and tells them what's really going on only for the timeline to change around them! Obviously, something has gone wrong with Command's mission, and per usual, it's now up to Mariner, Tendi, Rutherford, and Boimler to save the day.