The lake water was bone-chillingly cold. Zhang Xiao had not yet used the Bubble-Head Charm, because looking through its bubble slightly distorted his view of the outside world.
Feeling his body heat rapidly draining away, he inwardly clicked his tongue. Then he heard several more muffled splashes.
Harry and the others had come down too. Zhang Xiao made a few simple gestures, telling them to take a moment to acclimatize.
The water beneath the ice generally stayed at four degrees Celsius, which was very cold indeed. These were much like the conditions that had frozen Jack to death when the Titanic sank.
Sure enough, the attempt to acclimatize revealed a problem. Zhang Xiao noticed Little Ma twitching slightly, his limbs as stiff as wooden poles.
They had no choice but to return to the surface immediately and climb into the warm tent with its burning brazier. Zhang Xiao waved his wand and dried Malfoy's clothes.
Hermione handed over a blanket and a cup of hot cocoa. The young witch looked pale herself, and was not doing particularly well either.
Shivering, Malfoy thanked her and gulped down a large mouthful of hot cocoa. Only then did he feel a little better.
"What happened?" Harry and Ron were baffled. Entering the water had been uncomfortable for them too, but neither had reacted so badly.
They had barely gotten into the water before seeing Zhang Xiao repeatedly signal for them to surface.
Cedric dried the other young wizards' clothes and fetched a few more blankets. He was quite understanding of Malfoy's predicament.
"Draco hasn't dived in water like this before, so he's having trouble adjusting."
Malfoy nodded and said, still shaken:
"Right. Once I went down, my heart started pounding, my ears kept ringing, and my hands and feet went numb. I couldn't