The U.S.S. Discovery battles against Control in a fight not only for their lives but for the future, with a little help from some unexpected friends. Spock and Burnham discern vital new connections between the red signals while Burnham faces one of life’s harshest truths: the right decisions are often the hardest to make.

Sonequa Martin-Green (Commander Michael Burnham)
Doug Jones (Commander Saru)
Anthony Rapp (Lt. Cmdr. Paul Stamets)
Mary Wiseman (Ensign Sylvia Tilly)
Shazad Latif (Agent Ash Tyler)
Wilson Cruz (Dr. Hugh Culber)
Anson Mount (Captain Christopher Pike)

Michelle Yeoh (Philippa Georgiou)

Jayne Brook (Admiral Katrina Cornwell)
Mary Chieffo (Chancellor L'Rell)
Yadira Guevara-Prip (Me Hani Ika Hali Ka Po)
Mia Kirshner (Amanda Grayson)
Tig Notaro (Commander Jett Reno)
Ethan Peck (Lieutenant Spock)
Rebecca Romijn (Number One)
Alan van Sprang (Captain Leland)
Rachael Ancheril (Commander Nhan)

Emily Coutts (Lt. Keyla Detmer)
Patrick Kwok-Choon (Lt. Gen Rhys)
Oyin Oladejo (Lt. Joann Owosekun)
Ronnie Rowe Jr. (Lt. Ronald Bryce)
Sara Mitich (Lt. Nilsson)
Raven Dauda (Dr. Tracy Pollard)
Julianne Grossman (Discovery Computer)
Zarrin Darnell-Martin (Nurse)
Glenn Hetrick (K'vort)
Thom Marriott (Council Member)
Hannah Spear (Siranna)
Samora Smallwood (Lt. Amin)
Hanneke Talbot (Lt. Mann)
Kyana Teresa (Doctor)
Chai Valladares (Lt. Nicola)
Nicole Dickinson (Yeoman Colt)

• Season 2 Finale.
  
• During the battle, the Klingons join the fight, followed by Kelpiens in Ba'ul fighters, including Saru's sister Siranna.
  
• Spock realizes Burnham is the one that sent the red signals. She goes to the past to bring Discovery to each of the five locations needed to complete the mission, starting with Reno on the asteroid. The sixth signal will lead Discovery through the wormhole and the final signal will tell Spock that Burnham is safe.
  
• When an undetonated photon torpedo embeds itself into Enterprise's hull, Admiral Cornwell has to manually bring down the emergency bulkhead, locking her inside with the warhead. She is lost when the torpedo explodes.
  
• Georgiou locks Leland in the spore drive reaction cube, then magnetizes it, destroying him.
  
• Burnham in the angel suit leads Discovery 950 years into the future. Suru, Stamets, Tilly, Reno, Nhan, Detmer, Owosekun, Rhys, Bryce, and Nillson are among those that remain on the ship and follow Burnham into the singularity.
  
• Pike, Number One, Spock, and Tyler are debriefed by Starfleet Command, and each reports that Discovery was destroyed. To keep Section 31 or anything else learning what happened, Starfleet classifies Discovery, its crew, and the spore drive.
  
• Ash Tyler had been acting commander of Section 31, and is formally named Commander of Section 31.
  
• The episode ends 124 days after the battle with Control, with the U.S.S. Enterprise repaired, and a clean-shaven Spock taking his place on the bridge. And the seventh signal is detected 51,000 light years away, in the Beta Quadrant.
  
• This episode was nominated for an Emmy Award for Outstanding Special Visual Effects.