How can you face a god?

After many adventures, Tanit and her family have acquired a mysterious object that a goddess tasked them with retrieving. There's just one small hitch: Millions of warships have suddenly appeared out of nowhere. To the girl's horror, the artifact she now possesses turns out to be the last key a Fallen God needs to free himself from his prison, and this will do literally anything to get hold of it.
They are trapped a thousand years in the future. There is only one way out - back to their time. The bad thing is that the Fallen God is not willing to let them escape.