War of the God Queen by David Hambling

Trainee architect Jessica is abducted through time to the Bronze Age, a captive of the nightmarish Spawn. She soon escapes and, with the help of their leader, rallies nomad warriors to fight the alien invaders.
Jessica lacks even the most basic skills to survive in a word which is particularly dangerous for women, and realizes she needs the help of others abducted from other eras. Personalities and cultures clash, friendships and romances blossom and alliances forged.
But the Spawn, seemingly unkillable, are rapidly growing in power. Defeating them is not just the only way to get home – it is the only way to save the human race and ensure she has a future to go back to.

Category: Science Fiction – Adventure