Two men, Paxton Frost and Ignatius, are joined and separated by centuries.
Paxton is the illegitimate son of a born again christen woman. An expert in baryogenesis, he joins a team in England testing M theory. Socially inept and emotionally immature, he finds security, if no comfort, in social isolation.
Ignatius is the bastard son of the Duke Despensers. After he comes of age, he enters into religious life. Second son to the duke, he is determined to live life and experience the world according to his rules.
An accident in a test sends Paxton crashing into medieval England. He is barely able to speak with the people of this this time. He has no useful skills and no way back to his world. Staying in a monastery, while awaiting trial as a warlock, he becomes friends with a postulant, Ignatius. Later, he falls in love with a prostitute, Beatrice.
Ignatius's lust for power and women turns him against the man he called "brother." He is now on a personal mission to destroy Paxton and Beatrice.
Paxton's team members manage to bring him back, but not without consequences, for Paxton, Beatrice, their unborn child, and history. He decides to go back and confront his "brother."