Sorcerer's ward
Barbara Hambly1994

Six years ago, Tibbeth of Hale was burned at the shake. His apprentice, Kyra Peldrin, in defiance of her family, decides to pursue her magic studies at the College of Wizards.
Now, a junior-level mage, Kyra is getting some unusual readings from the spells she is practising. Things become even stranger when one night Kyra wakes with the certainty that her sister Alix's impending marriage to Blore Spenson - weathly head of the Merchant's Guild - will end in Alix's death on her wedding night. Thus, determined to stop the wedding at all costs and to locate the source of the threat, Kyra returns to Angelshand and a machiavellian court full of hostility and dangerous secrets.
What she finds is beyon comprehension. The is definitely magic involved : but it is a magic that can't possibly exist. Can it ? Is the almost completely hidden hex-mark really that of her, now dead, former mentor...