The children were inseparable. Their parents had very few photos of Al without Cassie or vice versa. On several occasions, one child had gone on vacation with the other family because the two were so distraught over being separated for any length of time.
What puzzled Draco was how they would sit and play quietly, almost never speaking a word aloud.
He mentioned it to Luna one day. She of course, knew the answer.
"They don't need words." she said.