Burnham goes to Vulcan in search of Spock, where she unearths surprising family secrets. In researching what is left of the Red Angel’s signal over Kaminar, Pike and Tyler end up in battle with time itself. Georgiou has a few tricks up her sleeve for Leland and Section 31.

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)
Anson Mount (Captain Christopher Pike)

Michelle Yeoh (Philippa Georgiou)

James Frain (Ambassador Sarek)
Mia Kirshner (Amanda Grayson)
Ethan Peck (Lieutenant Spock)
Alan van Sprang (Captain Leland)

Hannah Cheesman (Lt. Cmdr. Airiam)
Emily Coutts (Lt. Keyla Detmer)
Patrick Kwok-Choon (Lt. Gen Rhys)
Oyin Oladejo (Lt. Joann Owosekun)
Ronnie Rowe Jr. (Lt. Ronald Bryce)
Julianne Grossman (Discovery Computer)
Arista Arhin (Young Michael Burnham)
Liam Hughes (Young Spock)

• This episode marks Ethan Peck's first on-screen appearance as Spock.
  
• Pike and Tyler send a probe into the temporal rift, and it comes back from 500 years in the future and breaches Discovery's computer. They interrupt the breach, but not before it appears to affect Lt. Cmdr. Airiam.
  
• When Leland confronts Georgiou about Burnham and Spock's escape, she tells him she knows he's the one responsible for the death of Burnham's parents.
  
• In his catatonic state, Spock recites the same sequence over numbers over and over: 8-4-1-9-4-7. Burnham realizes the numbers are backward, and the computer finds one planet at coordinates 749 mark 148: Talos IV. Burnham sets course at maximum warp. (Talos IV was the setting of the unaired pilot, "The Cage".)