Vashti is a pathogenic diplomat—an ambassador to the world of viruses, whom she communicates with through a machine that can translate their chemical signals into images, tastes, smells, sounds, and memories. She begins a negotiation between the US Government and a diplomatic contingent from Arenavirus, a virus which has just begun spreading a deadly mutation in Florida. If Vashti is successful, she and Arena will reach a diplomatic agreement; if not, the Arenavirus infection will continue to spread, and humans will have to race to try to find a vaccine or treatment. As she navigates the diplomatic discussions, Vashti is also trying to connect with her daughter Alma, who lives on the other side of the country in a technology-averse commune. By the time the negotiation ends, Vashti discovers that Arenavirus have learned some impressive and deadly tricks from their interactions with humans.