A possible concise summary is:
The narrator follows her crush James into a tornado shelter, only to find out that he has a girlfriend named Amy. They get trapped inside for a week, and Amy reveals that she planned this to prevent James from going to college. Amy also hides food, water, and a key from the others. The narrator and James bond secretly, and eventually escape with the key. James dumps Amy and kisses the narrator.
Here are the key facts extracted from the text:
1. The narrator was running in the rain and followed her crush James into a tornado shelter.
2. The narrator got trapped in the shelter with James and his girlfriend Amy, who were kissing and ignoring her.
3. The narrator and James secretly held hands and almost kissed at night, while Amy was asleep.
4. The narrator discovered that Amy had planned to trap James in the shelter to prevent him from going to college, and that she had hidden food, water, clothes and a key under a loose floorboard.
5. The narrator escaped the shelter with James, who broke up with Amy and kissed the narrator.