It is the suspicious death of one of these friends, Jo Lynn, that has brought him back. Jo Lynn had become a beta, a leader of her clade, and, we soon learn, she had become controversial in that community because of her advocacy of abortion of the pregnancies that began happening to beta girls at puberty. Pax's other best friend, Deke, became an argo, and he is also a leader of his clade, acting as a sort of unofficial police chief and, in his personal life, striving to overcome the sterility that inflicts argos. Pax's link to the charlie clade is his father, and eventually a woman called "Aunt Rhonda," his father's secretary at his church, who became Mayor of Switchcreek after the crisis.

Pax's time in Switchcreek is dominated by two aspects. He suspects that Jo Lynn's death was not suicide, as officially reported, and he engages in some rather diffident investigation, involving in part an invading journalist who was interested in Jo Lynn because he suspected she was the person behind a prominent blogger who speculated on the causes of TDS. The second concern for Pax is his father, aging but stubborn. His relationship with his father is complicated by the "vintage": somehow Pax's presence causes his father to produce it more readily, which intrigues both Aunt Rhonda (who seems to be involved in some form of trafficking of the "vintage"), and Pax, who accidentally becomes addicted.

Behind all this is the question: what is TDS? What causes it? Inevitably, that is of considerable interest to an SF reader -- this one certainly included. And this is where the novel fails to satisfy. Gregory posits a couple of explanations, but none really struck me as all that interesting. And in the end, he leaves that question open. The mystery of Jo Lynn's death is resolved in a fair and interesting, and rather wrenching, manner. Pax's relationship with his father is explored with honesty and, if not resolved, one can say it's treated believably. There is also considerable business about the political situation in Switchcreek: Aunt Rhonda's manipulations which can be considered borderline criminal but usually, or perhaps marginally, in the interest of the town's residents; and Deke's concerns with the argo fertility problem. These too are handled well enough.

In the end, I found the book worth reading, but underwhelming. The description of small town life in Tennessee struck me as spot on. The characters are quite believable, depicted with real clarity and honesty. The prose is quite fine -- not showy, nor particularly special, but very smoothly executed. The problems I had were with the plot, which is OK but not all that absorbing, and not really sufficient in itself for a novel of this length; but more importantly the SFnal content, which is teasing but unresolved. It's nice work -- I'm happy to have read it -- but in the context of Gregory's career, and in the context of the best SF novels of this time, it's a mild disappointment.