“Three, two, one-” Xavier leaned forward and whooped as he sped away down the stairs. I was a little more cautious but as the tray spilled over the edge, I couldn’t help but scream in excitement as it shot down the spiralling staircase at speed. I flew around and around, my hair pulled back behind me before crashing into the mattress at the bottom of the stairs and laughing as I tumbled across it. Xavier snatched my hand, dragging me upright and grinning so widely that for a moment it almost looked like he was glowing. “Again,” he demanded.