Star Trek Discovery Season 3: Everything You Need To Know
5. The Seven Signals
Departing Earth, Discovery receives a distress signal from the USS Enterprise, under the command of Captain Christopher Pike.
Captain Pikes boards Discovery and takes command with a new mission: Investigate a series of mysterious signals that have been appearing all over the galaxy, one of which has disabled the Enterprise. Michael is apprehensive about reuniting with her brother and Enterprise science officer, Spock, but it turns out he has taken a leave of absence to secretly uncover the truth of the signals himself.
Chasing one of the signals to the an asteroid field, Discovery stumbles upon the remains of the crashed medical ship Hiawatha and rescues several of her crew, including engineer Jett Reno. While on the asteroid, Michael is nearly killed and has a vision of a winged humanoid form we come to know as the Red Angel.
Starfleet informs Pike that, during his leave, Spock had himself committed, but escaped the hospital and killed three staff. Neither Pike nor Michael believes Spock is a murderer and a visit from Amanda (Spock's mother and Michael's adopted mother) reveals that Spock also had visions of the Red Angel.