Adaptation

What happens if us, humans, branched out into two different species group. One way superior than the other but greatly outnumbered, will we all live in perfect harmony or will one species rule out the other. (the second one of course!)
A girl, Leona, wanted to know more about the so called truth. A truth that could destroy her perfect little life. Will she risk it all for the greater good, a good that wont give her anything. How long would she be this selfless character?