“We are coming for you. Do not resist us or you shall all die.” These are the haunting words that teenager Heidi Kilbourne has been dreaming about for the past few months—that and a creature that is giving her night terrors.

When Heidi ventures into a storm drain near the railroad tracks in search of adventure, she stumbles right into the discovery of a lifetime: An ancient alien race who tells her they have watched over mankind since its inception, and they are here to prevent a catastrophic attack on Earth.

But are these aliens truly allies? Or is there something more sinister lurking beneath their claims?

Drawn into a group of humans recruited by the aliens, Heidi discovers a devastating secret and begins to question who the real invaders truly are.