Illyria by Elizabeth Hand
Maddy and Rogan come from a line of Shakespearean actors. They are the children of brothers; Maddy's family consists of only daughters and Rogan's family has only sons. Both families live in the family compound, and the houses are close to each other. Much comment is made about the "kissing cousins", and Maddy and Rogan have always been inseperable.
When Rogan finds an intricate toy theatre locked away in a storage room, the room becomes a refuge where he and Maddy can have peace...and eventually, sex. Rogan pulls away from real life as Maddy begins to embrace us.
This is a tragic novel that never pulls the reader into the characters. Although the form will appeal to literature teachers, teens will shrug after completing this (fortunately) short novella.