INVISIBLE THINGS

This sequel to The Explosionist (2008) initially sags under the weight of the explanation required to bring readers up to speed on the first book's intricate plot, in which events of world history are reimagined with alternate outcomes. The story finds its stride, however, in the further adventures of 16-year-old Sophie Hunter, who has escaped Scotland and found refuge at the Institute for Theoretical Physics in Denmark, where mysteries and apocalyptic menace continue to plague her. Aided by her loyal friend Mikael and her cat Trismegistus, Sophie takes on nuclear conspiracy and a Snow Queen straight out of Andersen. Davidson weaves elements of science fiction, philosophical inquiry and real historical figures—Alfred Nobel, Niels Bohr, Paul Dirac, Ludwig Wittgenstein—into the verbose third-person narrative. The number of unanswered questions still standing at the abrupt ending leaves no doubt of a continuation. (Alternative history/fantasy. 14 & up)