Professor Thomas Williams, a renowned physicist, believes that UFOs are not from outer space but from an ancient parallel world and that frequent sightings are a sign that the universe is becoming unstable. Attempting to prove his theory, he develops a way to travel between parallel worlds, a feat considered impossible according to quantum physics.
Facing persecution from the government and other adversaries, Williams and his teenage son Dan go into hiding separately. Dan receives help from Rio, a girl his age he just met, and together, they evade capture. Their journey takes an unexpected turn as they are thrust into a mind-bending adventure, traveling through various parallel worlds until they finally reach the oldest world, where they confront the origin of the UFOs.
The question remains: will Rio and Dan possess the strength and intelligence needed to find their way back home and do what is necessary to save their world?