Through the Valley of Shadows

A new signal appears over Boreth, a planet which is sacred to Klingons and has a monastery where Klingon monks guard time crystals. These are the same monks that Tyler and L'Rell left their son to be raised by. Pike visits the monastery to retrieve a time crystal and finds that their son is now a fully grown adult named Tenavik. Tenavik explains that life on Boreth is affected by the crystals and that if Pike takes one, he will not be able to change the future that it shows him. Pike sees a future where he is severely disabled in an accident but chooses to take the crystal anyway to serve the greater good. Meanwhile, Burnham and Spock investigate a Section 31 ship that had checked in ten minutes later than usual and find all of the crew dead except for one, Kamran Gant, an old colleague of Burnham's who has been possessed by Control and attempts to transfer Control into Burnham's body.

Summary from Wikipedia, CC BY-SA 4.0.