Imagine, for a moment, a time far in the future. Mankind has developed technology which enables travel throughout the galaxy, and other feats which today could only be understood as "magic". Expanding to the stars, we discover other races, far less advanced than ourselves, and begin to study them, concealed behind cloaking devices like in Star Trek: Insurrection, or even picking up samples of the population for experiment and study, usually wiping their memories afterwards so that they are none the wiser. Because with the very laws of physics at its beck and call, what remains to learn but the fundamentals of what makes people people? And what would be the harm, really, if some members of the lesser races were to occasionally experience a missing week... or month... or year...
But then something happens that nobody can expect. A small child, orphaned despite all the wonders of human science, begins to spend time with two of these alien test subjects. The child learns the creatures' ways, becoming a bit more like them. And at the same time, the aliens learn more of humanity. One of them, touched by the elements of our culture and ideas that were familiar to it, begins to treat the child as its own, taking upon itself the role of a mother to this orphaned youth. But as the one alien becomes increasingly familiar with our species, the other drifts in the opposite direction, its mind increasingly filled with mistrust of our methods and our motives. Eventually, it decides that it has to return to its planet, and does so without our knowledge, by way of technology stolen from us, the secrets of which the alien would spend the rest of its life trying to fully decipher.
Paranoia sets in among the leaders of Earth. What will this alien, already somewhat untrustworthy, do when it gets a full understanding of our technology? How would it, or indeed its species react to such power? Can we allow this knowledge to spread wantonly among a comparatively primitive race, a people we barely understand, with a culture so different from our own? No, the council eventually decides. This spread of technology into a primitive culture is deemed to be too dangerous, both for their own position and for the galaxy itself; to stop this leak, the alien civilization must be wiped out. And the human who knew the two aliens as a child, the only one to really understand their ways, is chosen to lead the invasion, to make it as thorough and quick as possible, to ensure that no trace of human technology remains for others to find.
Imagine the position that this youth has been thrust into. What would you do, if faced with a choice between betrayal of your parents and betrayal of your people? Would you be willing to wage war against your own father, for what your brethren consider to be the greater good? Or would save your childhood companions from their fate, even if it meant ostracism from your community today, and possibly risking the safety of your whole species?
It is one of those choices where neither option is justice for the one forced to choose. It is the kind of crossroads that forms the foundation of a tragedy.
It is a story that has been told before.