That Hope Is You, Part 2

Aboard Discovery, Burnham escapes Zareh and teams up with Book against Osyraa's forces, while Tilly's bridge crew sabotage the ship to break free of the Viridian. In the nebula, Saru and Culber, helped by Gray in a holographic form, guide Su'Kal face the fears built into his simulation. They learn that his anguish at his mother's death caused the scream that rendered dilithium inert: the Burn. On the ship, Book throws Zareh to his death and Burnham kills Osyraa. Book uses his empathic link with the mycelial network to power a spore jump back to the nebula, and the away team is rescued. Saru takes extended leave to help Su'Kal begin a new life on Kaminar. Vance promotes Burnham to captain of Discovery. The Emerald Chain collapses, Trill rejoins the Federation, Ni'Var considers doing the same, and Discovery sets out delivering dilithium to worlds in need.