Alhaitham and Kaveh had been friends for years, not by choice, but because when they were young their mothers were friends... now they had both grown up... and Kaveh was one of the few people who could understand and speak to Alhaitham.

This was because Alhaitham was deaf and mute, and he wasn't very interested in socializing with people who didn't understand him. With Kaveh, he had no choice, but he ended up becoming a great friend, so much so that Kaveh had even learned to use sign language to communicate with Alhaitham.

That day, Kaveh had gone to Alhaitham's apartment to get something to drink while they caught up on their week. Alhaitham opened the door for him and Kaveh greeted him in sign language.

"Hey, alhaitham... long time no see"