Our hero, a conservatory student named Eliana, falls in love with her roommate, Mira, who turns out to be someone other than she presents herself to be, and Eliana's adventures are spurred by her devotion to Mira, and what she learns about Mira's other identity.
FotF and TtS are set in a world with a variety of "commonplace" magic, that everyone seems to be able to do, with individuals having varying degrees of talent at it. The primary conflict is between two forms of religion, one a dual-deity system, and the other a monotheistic one, based roughly on Christianity, whose God is visioned as female. I'd have enjoyed these books purely on the basis of the first chapter's epigraph: "For God so loved Her only son, She redeemed the world."
I liked the way both the pros and cons of competing religious factions were portrayed, and the characters were sympathetic (if not always realistic) and interesting. Definitely worth reading!