I so desperately wanted things to be different, not stupid and empty. I never noticed how hard people work just to make existence bearable. All those things I despised, comfort, money. The things everyone spent all their time thinking about instead of God. They did it because the gods are intolerable. It must have taken centuries of struggle for people to forget magic. So much effort. And I brought it blazing back and threw the world into catastrophe. [loc 7348]
The concluding volume of the trilogy that began with Advent, Arcadia begins on an isolated island, Home, some time after the events of Anarchy. The oceans are impassable -- 'no one's crazy enough to risk the cursed ocean now' -- and the shores are littered with shipwrecks and corpses. Home, it turns out, is the Scillies, and protagonist Rory (who's ten years old) is, by the end of the first chapter, the sole male human on the island.
But not for long.
Arcadia is divided into five sections: 'Utopia', set on Home; 'Fantasyland', which takes Rory to a post-apocalyptic Cornwall; 'Fairy Tale', in which everything becomes rather more overtly magical, as well as blackly humorous); 'Eden', a magical place which lies beyond a famously impenetrable wall of briar roses; and 'Fall', in which a great many strands are knitted back together.
Rory turns out to be a greater part of the overarcing story than anyone, including himself, could have suspected. Shipwrecked Silvia, though, knows more than anyone about how and why magic returned to the world, and it's she who brings the three sisters (Ygraine, Guinevere and Iseult) together again. (For certain values of 'together', anyway.)
Some things are beyond mending, and Treadwell doesn't attempt to paper over the damage and suffering of Anarchy. He does bring the story (stories) full circle, and brings weary travellers to something like peace. But that peace is not a resolution: England -- the whole world -- lies in ruins, and there's no going back.
Everyone in this story has lost somebody close to them: everyone is changed, by the 'intolerable' gods or by their own experiences. Some are healed, some are transformed. It's not a happy novel, yet there are moments of sheer bright joy in it: and humour, too, as when Rory finds himself debating philosophy with a rather disgruntled dog-fox. And oh, there is magic: and it burns too bright for any to bear.
We're not going back to the way things were. No more forgetting.