It's possible that Tony has detected some sort of danger near the school. Since he cares about Peter, he calls to warn him. Maybe there are some bad guys scouting the area for a potential attack, and Tony wants Peter to be on high alert.
Tony might be calling to offer Peter an internship opportunity at Stark Industries. He knows Peter is smart and could benefit from working with him. And he doesn't want to wait until after school to tell Peter about this great chance, so he calls him at school.
One reason could be that Tony has a new project related to Peter's studies. He might want Peter to be involved in it, like a research project on some new material that could be used in Spider - Man's suit. So he calls him during school hours to discuss it.
Another reason could be jealousy. In some fanfictions, Tony might be jealous of Peter's natural abilities and the way he is so quickly embraced by the public. Peter, in turn, could be envious of Tony's resources and experience. These emotions can fuel arguments between them. Their relationship is complex and full of potential sources of conflict like this.
One possible reason could be jealousy. Maybe Peter has some natural talent or ability that Tony wishes he had, and this makes him mean. For example, if Peter is really good at something like coming up with innovative ideas quickly, and Tony, who is used to being the smartest in the room, feels threatened.
Maybe Pepper Potts could find out what Tony has done and rescue Peter. She might be able to talk some sense into Tony and make him release Peter.
Maybe Peter discovers that Tony has been keeping secrets from him that directly affect his life or safety. For example, if Tony has been secretly monitoring Peter without his knowledge, Peter might feel betrayed and cut ties.
It could also be due to external pressure. The media or some powerful figures in the fanfiction world might force Tony to stay away from Peter. They could spread false rumors about their relationship or use their influence to separate them for their own gain.
One possible reason could be that Tony sees a lot of potential in Peter. In the original story, Peter has great powers and a good heart. The fanfiction might explore different scenarios of their relationship, like a mentor - mentee relationship in more depth. Tony might be interested in how fans envision their interactions and the growth of Peter under his influence.
Pepper Potts might appear. She could play a role in helping Tony take care of Peter, like making sure he has a proper diet and a comfortable living space in the Stark Tower. She might also be a maternal figure to Peter, giving him advice on relationships and growing up.
In this fanfiction, Peter may face the challenge of finding Tony in the first place. Siberia is a vast area. He might have to rely on his spider - sense or some clues to track Tony down. Additionally, if there are other superheroes or anti - hero characters in the area, they could either help or hinder Peter's mission. And, of course, the physical condition of Tony when Peter finds him could also be a big challenge. If Tony is severely injured, Peter has to figure out how to transport him to safety while being chased by enemies.
It could be that Peter was in a hurry and didn't have time to talk. He might have been in the middle of something important in his own life, like dealing with school or helping a friend, and just had to end the call abruptly.
One possible reason could be that Peter might feel like he's a burden to Tony. Maybe he made a big mistake and is afraid of Tony's reaction. For example, if he accidentally endangered the lives of others during a mission while under Tony's supervision.