Moon’s Knight by Lilith Saintcrow

Drunk and disoriented after her best friend’s funeral, Ginevra Bennet stumbles through a door in an ivy-covered wall…and finds herself in a dry wasteland under a dying crimson sun, the only possible shelter a giant stone castle.

If it’s a hallucination, it’s a deadly one; the Keep is full of beauty, luxury, courtly manners–and monsters. The inhabitants rejoice in her arrival, dress her in white, and call her a queen. Greenery returns to their gardens, and the prince of the realm, with his silver-ringed eyes, seems very interested in Gin indeed. It should be the answer to every lonely young woman’s dreams.

But nothing in Gin’s life has ever been what it’s seemed. Not her best friend, not her upbringing, and most especially not her nightmares. Drowning, violent death, a stone roof, and the hallucinatory prince have filled her nights, and Gin hopes she’s going mad–because the alternative is just too scary to contemplate.

Caught in a web of manners, intrigue, and betrayal, Gin has to depend on her sorely tested wits and uncertain sanity. There are Gates at the edge of the wasteland, and if she can escape the castle and its beautiful, terrifying inhabitants, she might just find a few answers and be able to get home.

Assuming, of course, home is where she really wants to be…