Slave 4 Time Traveller — Andrew Fox

Rabert Ross and Li Ying are led to an ancient, lost city. Inside the city they find a time travelling device. Rabert and his motley crew of friends travel ten millennia back in time. Dragons fly overhead. The city is about to be attacked by a deadly enemy. Great space battles with deadly space assets. Cannibals. Their forces battle a robotic army. Invisible astral predators killing on command.