Will You Take My Hand?

Tyler suggests that a drone enter Qo'noS's underground, dormant volcanic system to covertly search the planet for targets. Discovery jumps to a cave near the system's entrance, and a party of Georgiou, Burnham, Tilly, and Tyler pose as traders visiting an Orion outpost on the planet. Tilly discovers that the volcanic system they are targeting is active, and that the "drone" Georgiou has is a hydro-bomb. Burnham confronts Cornwell, who admits that detonating the bomb in the active volcano will annihilate all life on Qo'noS and win the war for the Federation. Burnham insists that Starfleet not commit genocide, and convinces Georgiou to give up the detonator in exchange for her freedom. They give the detonator to L'Rell, who uses the threat of mass destruction to unite the Klingon houses under her leadership and end the war.

Summary from Wikipedia, CC BY-SA 4.0.