On Trill, Captain Burnham, Book, and Culber must pass a dangerous test to prove themselves worthy of the next clue. Adira reconnects with Gray and Saru’s first day as ambassador is complicated by his engagement to T'Rina.

Captain Burnham and Book journey into extradimensional space in search of the next clue to the location of the Progenitors' power. Meanwhile, Rayner navigates his first mission in command of the U.S.S. Discovery, and Culber opens up to Tilly.

While undercover in a pre-warp society, Captain Burnham is forced to consider breaking the Prime Directive when a local tradition threatens Tilly's life. Meanwhile, Culber tries to connect with Stamets, and Adira steps up when Rayner assigns them a position on the bridge.