The tempestuous romance between Niall Trevallyan, an English lord, and Ravenna, an illegitimate orphan he was supposed to marry. When Ravenna was born under the sign of a magic cross, Trevallyan dismissed the Celtic prophecy that he must marry such a woman or misfortunes will follow. Some 20 years of misfortunes later and now married to another, Trevallyan tries to correct his mistake.