Mariner, Boimler, and Tendi clash with their arch-rivals: Delta Shift. The U.S.S. Cerritos engineers go on mandatory relaxation leave.

Tawny Newsome (Ensign Beckett Mariner)
Jack Quaid (Ensign Brad Boimler)
Noël Wells (Ensign D'Vana Tendi)
Eugene Cordero (Ensign Sam Rutherford)
Dawnn Lewis (Captain Carol Freeman)
Jerry O'Connell (Commander Jack Ransom)
Fred Tatasciore (Lieutenant Shaxs)
Gillian Vigman (Dr. T'Ana)

Asif Ali (Ensign Asif)
Mary Holland (Ensign Moxy/Toz)
Charlotte Nicdao (Ensign Meredith)
Artemis Pebdani (Ensign Karavitus)
Paul Scheer (Lt. Commander Andy Billups)
Carl Tart (Lieutenant Kayshon)

• The opener shows Captain Freeman possessed by an alien mask, like in the Next Generation episode "Masks".