Scavengers

The Discovery is upgraded to utilize 32nd-century technology, including programmable matter. Vance sends other Starfleet ships on various missions across the remaining Federation space, but orders Discovery to remain at the ready for any rapid-response missions. Book's ship arrives unmanned and carrying a three-week-old message from him about a new discovery he has made: the black box for a Starfleet ship that was destroyed in the Burn. Burnham believes that she can use this black box to trace the origin of the Burn, but Saru orders her to remain on the Discovery in case Vance needs them. Burnham agrees, but then disobeys Saru's order by taking Georgiou in Book's ship to go find him. On the salvage planet Hunhau, Georgiou poses as a buyer looking for rare ship pieces while Burnham looks for Book.

Summary from Wikipedia, CC BY-SA 4.0.