In the near future, those who have passed away on Earth arrive in an ethereal city located between terrestrial life and the afterlife. A blind man, after passing, must cross a desert to arrive at the city; Jim Singer, a sandwich shop owner in the town, found himself on a train on the way to the city when he first arrived. Citizens arrive in this purgatory, and, although there are new arrivals every day and billions of residents, the city expands with new arrivals, never running out of space. Across the billions of unique stories of those who have passed into the city, the one element that unites them all is the faint sound of a beating heart that all city residents hear upon entering this purgatorial space. 

Luka Sims, a young male journalist in the city, begins a newspaper to interview residents about the beating heart sound-- and learns that only 20% of them are able to hear it after their arrival. He collects theories about its origins, arriving at the conclusion that the sound is the beating heart of those still alive on Earth, and that those in this purgatory only stay so long as they are remembered by the living. The dead remember their lived worlds, too: during a war when many new souls pass into the city, hubs of conversation emerge in neighborhoods, with residents trading information about countries and their military exploits, eager to hear about the world of the living. Some residents, when going about their daily lives, have flashbulb memories of their times on earth.

In a turn, residents begin to rapidly disappear from the city. Luka Sims begins to report on the phenomenon, and learns that there is a pandemic sweeping Earth and wiping people out from the living world; they stay only transiently in the city, for a matter of hours, before disappearing. The oldest residents of the city feel these changes most prominently, as they are the ones with the most routinized lives. Mariama, a long-time caretaker at the city’s orphanage, disappears around the corner of a building one day never to return. Ville, a regular at the city bar who has grown used to drinking and spending time with his friends every evening, disappears one night— his friends from the bar come to his home to discover only his clothes and wristwatch in his home. Virologist Ethan Hass, in distress over the discovery that the virus was man-made, locks himself in an art gallery bathroom to cry; when a security guard breaks down the door, Ethan has vanished. 

There is no solution to this vanishing. Left in a nearly-empty city on the steps of the city church, a blind man— the same one who crossed the desert to arrive in the city— stands and listens as the city grows quiet. When no one answers after he shouts out, he puts his hand to his chest, feeling his own heartbeat and wondering if there is still any beating heart beyond his own.