It is 1483. Father Felix Fabri has set sail from Germany to Mount Sinai on a pilgrimage to venerate the relics of the spiritual bride he took when he first swore his vows, the martyr Saint Katherine of Alexandria. Following a tempestuous sea voyage, his group visits shrines throughout Greece and Palestine to pay homage and celebrate her life. Each time they come to worship, however, they find that the remains of Katherine's body are being stolen in bits and pieces; her hand, her ear, and then her tongue are missing from their holy resting places. Desperate to discover the thief and save his saint from such a brutal fate, Felix is thrust into a deep and strange mystery that takes him across the desert and plumbs the depths of his soul.