When he is awarded a fellowship at the Smithsonian in Washington, DC, he runs away from home and sets out on a great American journey. The inverse of his forbears who travelled westward as settlers, he leaves the land of his childhood, "the land of myths", and heads east, to "the land of ideas". In doing so, he fulfils another American myth: that of the humble country boy who winds his way towards the seat of his nation's power. But along the way he must puzzle over his brother's death, the uncertainties of his relationship with his parents and of the incongruous pair's own relationship - and over the most eloquent questions of science itself. The road is fraught with danger and in times of crisis T. S. has a charming habit of first considering, then wailingly assuming, that he is already dead. But when his mind starts to scamper over the scientific and philosophical ramifications of such a death at such a time, it gives him the strength to carry on: "I still had a speech to deliver in Washington. I had not even finished the Montana Map Series for Mr Benefideo!" 

In the quieter interludes, he reads from a notebook of his mother's that he stole on impulse before he left, and he discovers that it is not a taxonomic study but an historical novel about their ancestor, a pioneering female scientist. As T. S. reads, so do we, and in this parallel text some of his questions are answered. At one point, he absent-mindedly illustrates something in the margin of his mother's book and scolds himself for this professional trespass. But then, a few pages later, he encounters a note of hers in the margin that reads, "T. S. will illustrate?": "She wanted me to illustrate? My eyes filled with tears. I must have somehow already sensed her wish for us to collaborate. To collaborate!" This is the thematic and structural crux of a novel in which truth and love throb at the corners of our eyes, in the margins of life, waiting to be discovered.