Gellert laughed and splashed her back, treading water in place even though he could easily have rested his feet on the lake floor. He preferred to feel as if he could not; as if he was out too deep for it to be possible.
"Don't worry, you cannot fall ill from being out in the cold," Gellert said, finally falling to float on his back as well. "It's the staying cooped up inside that makes people sick in winter." Especially at schools like Hogwarts and Durmstrang, with so many students in such close quarters, exchanging viruses and bacteria. Gellert had been fortunate in that he never caught the influenza strains that seemed to circulate annually about the school. He never seemed to get sick at all, actually--until he had come to Lockewood, that was.
The sun was blinding and Gellert lifted a hand to shield his eyes slightly, to little effect. "Not particularly," he answered her, kicking lightly to propel himself in her direction. It was a lie, a great one, but there was no tell in his voice. "What about you? Still playing a lot of chess?"