The story is about Amisa, a high school girl from Tokyo who moves to Osaka to live with her aunt. She's determined to find a cure for her younger sister Moriko's rare allergy that makes her sensitive to sunlight. At her new school, Amisa meets Tomi, a boy who shares her passion for science, and they start working together to find a cure. Despite initial obstacles and setbacks, including the school's rejection of their proposal and the interference of Tomi's girlfriend Cowrie, Amisa and Tomi eventually succeed in developing a medicine that helps Moriko. With the help of Amisa's aunt, who donates to the school's science department, they're able to fund their research and make the medicine a reality. In the end, Moriko is able to go outside and enjoy the sun, and Amisa confesses her feelings to Tomi, who has recently broken up with Cowrie.
Here are the key facts extracted from the text:
1. Amisa was born to parents who treated her like their world.
2. Amisa's sister, Moriko, has a rare allergy that makes it hard for her to be in the sun.
3. Amisa's parents moved to a new home and Amisa stayed with her aunt in Osaka to attend a new school.
4. Amisa's new school has one of the best science laboratories in the world.
5. Amisa met a boy named Tomi on the bullet train to Osaka.
6. Tomi is Amisa's classmate and has a girlfriend named Cowrie.
7. Amisa and Tomi started working together on a science project to find a cure for Moriko's allergy.
8. Amisa's aunt, Hina, is an artist and has five children who are trying to sell her paintings and house.
9. Amisa's school rejected her proposal to fund her research project.
10. Aunt Hina sold her house to donate the money to the school's science department to support Amisa's research.
11. Amisa and Tomi successfully developed a medicine to cure Moriko's allergy.
12. Moriko was able to go outside in the sun without getting a rash after taking the medicine.
13. Amisa and Moriko visited Aunt Hina's apartment, and Moriko thanked Amisa for everything.
14. Amisa realized she had feelings for Tomi and decided to tell him.
15. Tomi and Amisa's sister Moriko seemed to have a connection, and Moriko ran to him when he arrived at Aunt Hina's apartment.