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.
That setting is the rough timeframe that precedes the first season of "Picard," with the Romulan supernova, the attack on Mars, and various other events of that nature being relatively recent history.