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.
On the way to the next clue, the U.S.S. Discovery is sabotaged by a mysterious weapon, leaving Captain Burnham, Rayner, and Stamets as the only crew members who can possibly save the ship in time.
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.
On Saru's last mission as Captain Burnham's Number One, the team ventures to a seemingly abandoned planet to hunt for what might be the greatest treasure in the galaxy.
Captain Burnham and the U.S.S. Discovery are sent to retrieve a mysterious 800-year-old Romulan vessel; until the artifact hidden inside is stolen, leading to an epic chase. Meanwhile, Saru is offered the position of a lifetime, and Tilly's efforts to help pull her into a tangled web of secrecy.
Follow the voyages of Starfleet on their missions to discover new worlds and new life forms, and one Starfleet officer who must learn that to truly understand all things alien, you must first understand yourself.