Dusk in the swamp clicks and thrums with the sound of frogsong. Bigger things, and more dangerous, stir in the shadows and in the deeps, but for now no tooth nor claw can be seen. The air is thick, with moisture and with waiting, and with dangling matted creepers and all manner of tiny winged things that buzz and bite. In the branches above, dripping with humidity, and the sky beyond, pinpricks of light wink one by one into being. The power circle has been drawn – there are works dark and vital to be done here before full night falls.