Napping Princess: The Tale of the Unknown Me

Kokone should be diligently studying for her university entrance exams, but she just can't seem to stay awake. Aside from stealing precious study time, her napping is even more distracting, as it brings on strange dreams with warring machines that hint at family secrets that have been dormant for years. She can't ask her father, as he's always busy modifying motorcycles and cars in flights of fancy. What are these visions that lead Kokone at once closer to and farther away from her family?