An American army doctor, Major Grayson Pierce, finds a little boy hiding in a stench-filled barrack at the Buchenwald concentration camp in April 1945. A devout Catholic, Pierce realizes that God is allowing him to save one precious life among the ubiquitous piles of naked corpses in this notorious Nazi slave labor camp. After the war, the doctor, a widower, brings Joe to him home in Ithaca, New York, and becomes his guardian. At the Pierce mansion, Joe struggles with his nightmares of Buchenwald and with three old women who see him as an intrusion--Grayson's "fire-breathing" mother, Nina Cassandra, his "drill sergeant" older sister, Mildred, and a benign but indifferent Aunt Elvie. Making things worse is Grayson's eight-year-old insolent daughter, Irene, who refuses to accept Joe as her new "brother." Grayson nearly comes to blows with his mother and sister when he chooses to rear his ward as a Jew while they insist that the boy must be converted to Catholicism. To escape the family "pressure cooker," Grayson and Joe take a two-week excursion around New York State. Joe learns English and bonds with his guardian in trust and love. Back at the mansion, he is better prepared to deal with the old women, but the bitter fight over his soul continues for the next several months, coming to an acrimonious conclusion at Christmastime. The Guardian's Son is a story of how the devastating memories of Buchenwald affect a young boy and his guardian, and how religious intolerance, hypocrisy, and racism poison a deeply religious family. In the end, hatred, bigotry, and anti-Semitism are overcome in Christian values of benevolence, kindness, charity, and compassion in this powerful story.