Pulled into a parallel universe, Mariner is swapped with her alternate self, a strict captain, while Tendi leads an Orion pirate crew for her sister.
The fifth and final season opens with the Cerritos pulled into a parallel universe where the crew made slightly different choices. The alternate ship is captained by a stern disciplinarian version of Mariner who longs to be a carefree junior officer again, so she kidnaps the real Mariner and takes her place. Mariner escapes, persuades the alternate crew to signal her ship, and the two swap back as both crews work to send the Cerritos home.
In a parallel story, D'Vana Tendi captains an Orion pirate crew to pay off a debt to her sister D'Erika by salvaging a derelict Orion medical ship. A clash with the rival Blue Orions ends without bloodshed but sparks a clan war, and Tendi delays her return to Starfleet to help her family.