So "Brother"....
Spoiler
Michael is disappointed the science officer is not Spock as she'd anticipated. Pike informs them with the Enterprise out of action, he has been ordered to take command of Discovery to investigate these mysterious red signals. The Enterprise computers went haywire whenever they tried to scan them, leaving the ship completely disabled (yet somehow made it almost back to Earth on its own power?). Discovery departs to the closest and only remaining signal they'd detected. Along the way Sarek talks to Michael, where they both say they haven't talked to Spock in years, with Sarek picking up that Michael is not telling him something, but he doesn't press her about it. But instead of a red...whatever, they drop out of warp into a field of asteroids (their sensors couldn't detect that beforehand?) They quickly discover a crashed Starfleet medical frigate, but their arrival has acted like an opposite magnet to the asteroid, pushing it towards a pulsar it will impact with in about 5 hours. At this point, Sarek apparently returns to Vulcan on a shuttle.
Unable to get a transporter lock, Michael and the Enterprise crew take "landing pods" through the asteroids (where the science officer is killed while refusing to listen to Michael) and Michael is forced to save Pike after his pod is damaged as well. Inside the ship, they find an engineer who has kept several critically injured officers alive because they're all "basically machines" and she can read ( pretty sure you need to know a bit more than just what's in a text book to be able to pull off what she did). Michael quickly repairs the ship's transporters, and they evacuate the ship, but she ends up locked out of the room. While running to the transport enhancers they set up as a backup, she's injured and sees a red angel... which disappears as Pike returns (somehow) to save her. Back on Discovery, they take a chunk of the asteroid with them after Tilly noticed the spores reacted to the gravity field the asteroid gives off. Discovery returns to Enterprise (which is being towed to a starbase) and Pike lets Michael knows he and Saru will have "joint custody" of Discovery as they investigate the red signals. Michael asks to see Spock, and Pike admits Spock took leave. Investigating his quarters, Michael listens to his last personal log, in which Spock says he has been having nightmares, in the form of the red signals...
I really don't get why no one asked the obvious questions about Spock in this episode, other than to artificially prolong the drama. Michael says early on to Pike that she expected to see Spock, only for Pike to tell her to set her expectations low. What kind of a reply is that even? It's not until the end of the episode, when she explicitly asks to see Spock, that Pike tells her he hasn't even seen Spock in a while, because he's been on leave. Why wouldn't Pike have brought that up earlier? The same thing with whatever happened between Spock and Michael. Sarek goes out of his way to point out he can tell Michael isn't telling him something, which she does say is her fault, but... They really don't go into it beyond that, which seems odd they wouldn't actually talk about it when they'd brought it up.