When a new signal appears over Saru's home planet, Burnham, Saru and the crew embark on a perilous mission that puts Saru in danger and raises questions about the Red Angel's intentions. Hugh struggles to come to terms with his new reality.

A fourth signal leads the U.S.S. Discovery to a world where Pike is forced to make a life-changing choice. Burnham and Spock investigate a Section 31 ship gone rogue, leading to a discovery with catastrophic consequences.

Reunited with Burnham, Discovery heads to Earth to find out what has happened to the Federation in the last thousand years.