This is harem right. It looks mostly contemporary? I wonder how the author "justifies" the harem to the reader without the usual fantasy world culture stuff.
I can actually answer that I think now that I've listened to a bit of book 1. The setup is the characters are on a UN ship there to test some kind of new multidimensional drive, and there's navy personnel from many countries and dignitaries (mostly nuclear powers). The protagonist is an Aussie naval engineer, whose been tasked with looking after a group of naval personnel from these various countries who are all women (and being used to promote women in the navy). Going to guess the drive works but strands people in another dimension or time.
Makes me think of the film, The Final Countdown, that sends an aircraft carrier back in time to WW2 to stop Pearl Harbour.