Rails must be freshly laid ahead of the city & carefully removed in its wake. Rivers & mountains present nearly insurmountable challenges to the ingenuity of the city's engineers. But if the city does not move, it will fall farther & farther behind the optimum & into the crushing gravitational field that has transformed life on Earth. The only alternative to progress is death. The secret directorate that governs the city makes sure that its inhabitants know nothing of this. Raised in common in creches, nurtured on synthetic food, prevented above all from venturing outside the closed circuit of the city, they're carefully sheltered from the dire necessities that have come to define human existence. Yet the city is in crisis. People are growing restive. The population is dwindling. The rulers know that, for all their efforts, slowly but surely the city is slipping ever farther behind the optimum. Helward Mann is a member of the city's elite. Better than anyone, he knows how tenuous is the city's continued existence. But the world he's about to discover is infinitely stranger than the strange world he believes he knows so well.

    As one of the thousands who fled the outbreak of nuclear war in an alternate United States—an alternate timeline—she finds herself living as a refugee in our own not-so-parallel New York. The slang and technology are foreign to her, the politics and art unrecognizable. While others, like her partner Vikram, attempt to assimilate, Hel refuses to reclaim her former career or create a new life. Instead, she obsessively rereads Vikram’s copy of The Pyronauts—a science fiction masterwork in her world that now only exists as a single flimsy paperback—and becomes determined to create a museum dedicated to preserving the remaining artifacts and memories of her vanished culture.But the refugees are unwelcome and Hel’s efforts are met with either indifference or hostility. And when the only copy of The Pyronauts goes missing, Hel must decide how far she is willing to go to recover it and finally face her own anger, guilt, and grief over what she has truly lost.