Ancient Enemies Future Heroes

What if earths history as we know it is only a fragment of the actual truth? What if it started thousands of years before we ever thought? Could it be possible that an advanced society and civilization thrived here on earth, but due to a worldwide flood, their existence was nearly wiped away from history? With melting glaciers at the end of the last ice age then combined with a comet colliding with the earth, it caused global rainstorms and increased volcanic activity resulting in the rapid melting of earths ice. It quickly flooded earths entire surface. After over a month of flooding, only a small fragment of earths inhabitants survived. Many civilizations and creatures were totally wiped away. Many great cities were buried or sent to the bottom of seas. Animals and humans had to start over with repopulating the earth. Over time, some evidence of this time has been found. Some of these items found are more advanced then we are today. Some items are even questionable if they are even from earth. Only a few left today really know the truth about our planet. An alien race came to earth to escape their dying world. They tried taking over and ruling our world and all its inhabitants. After many hundreds of years, a civil war broke out among them with the human race getting caught in the middle. After a last-attempt battle to end the war, both sides were sent into hiding and waiting. Now in todays world, the aliens are once again planning their takeover of our world with their extinction agenda. They have already started influencing our society. A small group of individuals have been tragically brought together after their ancestors were eliminated by the aliens because they were being seen as threats. Now this small group is the only one in the aliens way of global domination.