When an unfamiliar pigeon flew to Ruben Nilsson's dovecote, no one could yet know that this bird was fatal. Infected with bird flu, she becomes the cause of a terrible epidemic that affects all of Gotland. Local authorities are taken by surprise, there is not enough medicine or vaccine, and patients are dying one after another. Amidst the panic that gripped the island, it was easy to overlook the strange death of a nurse at a large medical center and the mysterious disappearance of a local reporter. But police inspector Maria Vern and her colleagues do not give up their efforts and in the end they not only identify the killers, but also expose a much larger criminal project.