This experimental novel makes bold use of the Copenhagen interpretation of quantum mechanics, according to which there are innumerable parallel universes in addition to the present world that we all experience as reality. Yukito Ashifune, 36, is an associate professor of literature at university and an author whose work has been shortlisted for a prestigious prize. His wife, Yurika Oshima, five years his senior, used to be his editor. Their marriage is unhappy and childless. One summer day in 2007, Yukito gets an e-mail from someone calling herself Fuko. She claims to be his daughter living in the year 2035. As they mail each another, Yukito starts to believe in her, and in March the next year, following her instructions, he heads for Arizona. There he gets a phone call from Riki, Yurika's son from a second marriage, who urges him to return home. At the airport he is met by his wife and Fuko, then two years old. Thanks to Fuko and Riki reaching out from a parallel world, the family has slipped into another universe. Back in the original world, Yukito is arrested in Arizona as a suspect in an attempted terrorist attack. Meanwhile, in the parallel universe where the family now resides, a series of globally coordinated terrorist atrocities take place, targeting the opening ceremony of the Beijing Olympics in August 2008. While visiting a shopping mall in the Tokyo suburbs, Yukito and his family get caught up in the violence, and his wife and daughter are shot dead. Quantum Families provokes us to think about the fragility of human existence and the destiny of the family unit in the Internet age.