Jonathon Bridge has the corner office, the tailored suits and the impeccable pedigree. He has a fascinating wife, a child on the way and a string of nubile lovers on the side. He's a man who's going places. His world is our world: the same chaos and sprawl, haves and have-nots, men and women, skyscrapers and billboards. But it also exists alongside a vast, self-sustaining city-state called The Fortress where the indigenous inhabitants - the Vaik - continue to live much as they have always done. The Vaik is an all-female civilisation.

The Fortress is cloistered from the outside world and connected to it by an arcane tradition that permits female victims of male violence to order their assailants into The Fortress indefinitely. Another way a man may enter The Fortress is as a supplicant. When Jonathon's pregnant wife Adalia discovers the ugly sexual violence pervading Jonathon's top-tier firm, she agrees to continue their fractured relationship on one condition: that Jonathon become a supplicant for a period of one year.

Jonathon's arrival at The Fortress begins with a recitation of the conditions of his stay by Mandalay, the Vaik to whom he is assigned: he is forbidden to ask questions, to raise his hand in anger and to refuse sex. At times self-justifying, at other times lost, Jonathon is utterly unprepared for what will happen to him over the course of the year - not only to his body, but his mind and his heart.

The Fortress is a psychological examination of the dark heart of modern masculinity. It is interested in what male sexual submission looks like and how a female civilisation might operate. It wants to know if listeners can be aroused by sex scenes that have nothing to do with female objectification - and even if such arousal is possible. It asks questions about consent, power, love and fulfilment in a pacey, explicit and confronting listen.