Dr. Kovich sends Discovery after an 800-year-old Romulan ship, beginning a race against the couriers Moll and L'ak for a clue to Progenitor technology.
Dr. Kovich gives Burnham a secret mission to investigate an 800-year-old Romulan science vessel, but the couriers Moll and L'ak take an object from it first. Kovich enlists Book, now serving a sentence for his actions against the Federation, to help track them, and Book leads Discovery and the USS Antares to the planet Q'mau.
There the couriers learn from an android named Fred that the object is a Romulan puzzle box holding a journal, then kill him and flee. The Antares' captain, Rayner, sets off an avalanche during the chase, and Burnham uses both ships' shields to protect a town while the couriers escape. Kovich reveals that the journal belonged to 24th-century scientists searching for the technology the Progenitors used to seed life across the galaxy. Michelle Paradise wrote the final season's premiere.