Cybele, with Bluebonnets

From Booklist:

"Joseph first encounters Cybele when he is a 10-year-old skipping rocks, but he falls in love with her in high school, where she is his chemistry teacher. After he graduates, they have a whirlwind romance, but she won't marry him because she knows things about the future that she won't reveal. She encourages his affinity for chemistry, though, cementing his dedication to the science. Thereafter, miracles abound, both scientific and supernatural, and Cybele seems to look after Joseph even when she is no longer around him. With the help of her spirit, Joseph works for the police in solving the case of the Holy Grail and for the government during World War II. Harness' writing is delicate and seductive, effectively balancing chemistry and Joseph's life and love for Cybele. If the ending is abrupt, it works well as a transition to a new phase in the relationship with Cybele."