A chance meeting at a country entertainment and a mistaken identification separates engaged lovers. The mystery is unfolded months later in Rome through a woman's collapse in church, her tale of seduction by a married officer, and her love for her twin sister. A deathbed reunion of the sisters - and the separated lovers - is arranged by the English officers who wrongly identified the sister in the first place. Includes brief description of rites observed in Rome on Maundy Thursday - flagellation etc. Ruined twin sister dies as a result of seduction, betrayal etc. (PB)