The Numinous Constraint Agency is an extra-dimensional, multi-dimensional bureau tasked with maintaining a balance in the multi-verse in the spirit of a grand bargain called 'The Trinity'. It is headed by a dream-creature called 'Arteus the Faun' and it is staffed by variously talented Agent recruits. These are through the annals of The Agency Tales revealed to the author with dream-sendings. The staff of the Numinous Constraint Agency are drawn from the ranks of forgotten gods, demi-gods, mythical creatures of various types, also mortal Human beings who uniquely possess a 'tongue of flame', whom are thus called 'torches'. Swan and Song tells of the mission of the demi-god Rusta Barca and his ex-CIA mortal torch-probate Vernon Duke to locate and rescue a Black Swan from an eternity of torment. While doing so, they are able to free a Dream by accompanying its performance on Leonardo da Vinci's Viola Organista.