Mosaic Spiral summary:

Mira attends a private school in England and finds out that the boy who appears in her dream since her childhood really exists. He's Radley Macchiavelli, a beautiful model. When the two finally meet, the boy is transported to a parallel world connected from one spiral ("Rasen"). Mira follows him to try to save him and is swallowed into the parallel world dominated by the mysterious Black King…