A Viking in Atlantis - Vikings of the Bronze Age, #3

Accidentally thrown back in time to an ancient Greek island, brilliant scientist Katherine Bishop must form an alliance with her unwilling companion, a Viking named Ned with his own mysterious past. However, they soon discover all is not as it seems. As these two castaways struggle to survive in a hostile and suddenly unpredictable world, they find themselves falling in love, knowing it is impossible.
Their lives are separated by four thousand years, and if they can escape an island about to explode, they'll never see each other again.