Uhura meets an older version of herself in a timeline where Scotty is dead and helps the Midwives protect a newborn whose birth is distorting time.
Uhura investigates a white hole and is pulled into contact with an older version of herself, learning that Scotty has died in that future timeline. The two Uhuras swap places after another disturbance and each sees the other's crew and changed life.
The strange music and energy pulses prove to be a warning from the Midwives, who are protecting a newborn whose difficult birth is causing the disruptions. The two women reposition the child, restoring the timelines while keeping their memories. Scotty survives, and the season ends with both Uhuras embracing the lives they have now.