The Protostar's reunion with U.S.S. Voyager has unexpected side effects, bouncing the crew between alternate realities — including the mirror universe.

Kate Mulgrew (Vice Admiral Kathryn Janeway)
Brett Gray (Dal R'El)
Ella Purnell (Gwyn)
Jason Mantzoukas (Jankom Pog)
Angus Imrie (Zero)
Rylee Alazraqui (Rok-Tahk)
Dee Bradley Baker (Murf)
Jimmi Simpson (Drednok)
John Noble (The Diviner)
Robert Beltran (Captain Chakotay)