At the beginning of a 2 minute prologue containing no dialogue and only music, we see 2 students in detention, for an unkown reason. They both leave quite soon after we see them, about 5 seconds apart.
After they leave, they both go to a storage room in the school, as they have both left something in there. One enters first, and the other follows, in the same order as the detention room.
After both enter the room, they proceed to get their things. However, shortly after this, one of the two realizes that the door may have locked from the inside behind them. He tries to open the door, but it is locked. They try to get the attention of anyone outside, however there is only one student in the room who can not hear them.
They quickly start bickering, and it is clear that the characters may have a grudge towards eachother that is beyond being stuck in the room together.
After bonding over music, we learn that they had a fight, but they have quickly gotten over it and become friendly. They gain the motivation to find tools to get them out of the room.
The teacher who was supervising them in detention suddenly comes in to get something. It is revealed that the boys were in there for a very short period of time, but we can sense that it has made them closer than they ever would have expected.