In my book, an alien race conquers the earth and kidnaps the most intelligent or prominent people in certain branches of science where they consider that humans are more advanced.
Shortly after, a woman who is one of the best economists manages to buy her own freedom in this empire (becoming the first free human). The empire, however, is so gigantic that no one cares, as long as it follows the laws.
The economy of this empire is based on the control of a single substance that allows interstellar jumps, in addition to the use of weapons that make their bearers practically invulnerable. But above all, and most importantly, this substance also allows rejuvenation of its wearers.
On the other hand, apart from this type of material. The second generator of wealth is related to services such as: interplanetary communications, exploration of new worlds, and exchanges of raw materials.
Other important details of the setting:
- this empire has reasons to prohibit the study of Genetics
- only the empire's ships can fly into space, so no one can produce new routes of space travel
- communications between planets are made thanks to a species, also conquered and controlled, which communicates telepathically regardless of distances.
What economic weakness could this human take advantage of to buy her manumission, and then that of many other humans?