Seventh century England; a baby is found in a tree by a party of monks. He's brought up in their monastery and given the name Arborius. Young Arborius appears to have miraculous powers, so he's awarded a halo (second-hand, source uncertain)—but all is not as it seems. His "miracles" are really the work of his guardian spirit, a foul-mouthed thin dog, visible only to himself and to the slowest-witted of his fellow monks.

This biography of a little-known (actually non-existent) saint reveals how Arborius ostensibly earned his halo, worsted the Devil, was famed for feeding the poor and healing the sick, founded many of our Christmas traditions, departed the world in a manner recalling the tale of Jack and the Beanstalk—and was canonised.

Warning: the story contains groan-inducing word games!