This story begins on a windy summer's day in the Chilterns when the calm, organised life of Joe Rose is shattered by a ballooning accident. What happens is shocking and tragic, but strangely inconsequential. The consequences come after, for that fatal accident brings Joe together, briefly, with Jed Parry. Unknown to Rose something passes between them - something that gives birth in Parry to an obsession so powerful that it will test to the limits Rose's beloved scientific rationalism, threaten the love of his wife Clarissa and drive him to take desperate measures merely to stay alive.