Sephy sat at her desk, staring out of the classroom window. The lesson was about the history of Albion, but she wasn't listening. Her mind kept wandering to yesterday's conversation with Callum. He'd seemed so angry when she'd mentioned the beach party at her house. She couldn't understand why he was being so difficult about it.

Mrs Paxton, their Cross teacher, was explaining about the Liberation War of fifty years ago. "The Crosses fought bravely to maintain order and civilisation," she said, writing key dates on the whiteboard. Sephy noticed how Callum's jaw tightened every time Mrs Paxton spoke about Cross victories over the nought rebels.

At break time, Sephy hurried to find Callum by the old oak tree where they usually met. But he wasn't there. Instead, she found him sitting alone in the library, his head buried in a book about nought history - a book that wasn't on the school curriculum.

"Callum?" she whispered, sliding into the chair beside him. "Why weren't you at our usual spot?"

He looked up, his pale eyes filled with something she'd never seen before - disappointment. "Sometimes, Sephy, I wonder if you really understand anything at all," he said quietly, closing the book and walking away.