Captain Freeman assigns the Lower Deckers an overly safe mission to try and keep a self-destructive Mariner out of danger.

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

Robert Duncan McNeill (Nick Locarno)

Eric Bauza (Gem)
Jon Curry (Captain Ma'ah)
Gabrielle Ruiz (Lieutenant T'Lyn)
Paul Scheer (Lt. Cmdr. Andy Billups)
Lauren Tom
Paul F. Tompkins (Sub-commander Vrek)
Kari Wahlgren (Captain Cosmia/Key'lor)

• The U.S.S. Cerritos has been tasked with finding former Starfleet cadet Nick Locarno, who was introduced in the Next Generation episode "The First Duty".
  
• Mariner was friends with Sito Jaxa, who was also introduced in the episode "The First Duty", then later killed in the episode "Lower Decks". This is one of her reasons for not wanting to be promoted. She also knows Nick Locarno, and likely Wesley Crusher.
  
• If Mariner was in the Academy in 2368, that would likely age her in her late 20s/early 30s.
  
• Robert Duncan McNeill returns to voice Nick Locarno, who is revealed to be behind the mysterious attacks.