From the introduction:
"Welcome to the motor yacht Spiral Star, property of Captain Mary Putney, the celebrated and reclusive fantasy novelist. You were all friends or acquaintances of hers at one time, but none of you has had much contact with her in the past decade. Tonight, however, was her fiftieth birthday party, and you received a calligraphy invitation to remote Lake Irene in northern Minnesota. Who knows how many people got invited; you are the only guests who showed up. Some of you knew her from college or school, some as family, some through fandom, and some professionally. It turned out that none of you was a complete stranger to the rest of the guests either; each of you is acquainted with at least one other party attendee..."