Soundproofing
One day Isabelle was hanging out with Magnus in his room when she wanted some food so she yelled "Alex get me some food" when Alec didn't come she looked at Magnus mall he said was Soundproof. So Isabelle got up and went up to Alec and asked "Why is you and Magnus's room soundproof?" All he did was look away.
AN: I know I know. This is so badly written. I wrote it at 12:50 am. I'm tired well bye bye