From audible.com:

The ninth original novel tying into the critically acclaimed and much-missed Firefly series from creator Joss Whedon

It all started with the geese. The Firefly crew is eager to get paid for their latest job, but when payment arrives as a gaggle of geese instead of a purse, their stay on the planet Brome gets an indefinite extension. No matter that the geese will fetch a pretty penny once they get somewhere to sell them. Without coin, they can’t buy fuel, and without fuel, they can’t get offworld. Serenity is stuck.

Luckily the foreman of the local fuel refinery, Lyle Horne, wants to hire them, but not to work in the factory. He needs their help on a job only a crew like Serenity can pull off. Horne is an old friend of Shepherd Book’s. Mal would love to know more, but Lyle’s got bigger fish to fry. An authority known as The Governess has been kidnapping his workers. Lyle wants them back.

The crew need to break into her fortress of an estate and retrieve the workers. Jayne, who suffered a goose-related injury, stays behind to keep an eye on Horne while the rest of the crew split up to infiltrate the fortress. However, the Governess has her own story, as do the workers. Is Lyle lying? While they’re trying to make sense of it all, the workers’ children come aboard Serenity, with a plan to steal the ship and launch their own rescue mission.