Lady Blackbird is, for a tabletop RPG, a marvel of concision: in a mere 16 pages, it contains a slate of interesting characters, a marvelous world design sketch, cogent GMing advice, and an entirely workable game system.
It claims to be a "steampunk adventure," but it isn't particularly -- no Victoriana here. Instead, it's a sort of air wonder fantasy, the sort of thing you might expect in a Miyazaki film. It takes place in a "solar system" consisting of small planetoids with air between them, where skyships drone through the void, air pirates abound, and monsters like the sky squid are a continuing hazard to aerogation.
The scenario is that Natasha Syri, Lady Blackbird, a noble of the Imperium (the major power of the system) has fled an arranged marriage to be with her lover, the notorious pirate king Uriah Flint. She hired the smuggler skyship Owl, but it has been captured by the Imperial cruiser Hand of Sorrow, and she, her retainers, and the Owl's crew are now imprisoned within the cruiser's brig. The players take the roles of the imprisoned characters.
The game system itself is a variant of the dice pool scheme used in many "story games"; dice are rolled only for key conflicts, GM sets the difficulty, more dice are added if you use traits, tags, or character "keys," with each player having a pool of dice they can add, with dice pools depleting or being replenished at times. In short, the game system is small but workable, and aimed more at encouraging adherence to character and justification of actions through roleplay than at simulation.
You could have a good afternoon with this game, at a remarkably small investment in grappling with system and backstory.