When Monsignor Martin Heamey is found strangled just after a debate with Tony Cupelli, a former monsignor and present professor at Smith College, Tony's detective brother Mike seeks a possible link between this murder and the apparent suicide of a Carmelite nun in Brooklyn. The brothers uncover a growing cult of young women devoted to dark interpretations of the teachings and life of St. Teresa of Avila, a cult the brothers seek to prove guilty of the crimes, even as more possible victims of the devotees are revealed. When not one, but two, of Tony's present love interests are included among the most likely suspects, his own life is at risk unless, and until, the Cupelli brothers can decipher the clues awaiting in the secret writings of St. Teresa.