Well, in this kind of story, the main character is often the spy among friends. This person could be someone who has infiltrated the group for a long - term mission. The friends could include a joker type, always making everyone laugh and not suspecting anything amiss. There could be a serious and responsible friend who takes it upon themselves to investigate when they sense something wrong. And there could be a more emotional friend, whose reaction to the discovery of the spy is mainly based on hurt feelings rather than practical actions.