What happens to the kitten Hana at the shrine?

After Takagi and Nishikata spend their summer vacation caring for the abandoned kitten at the shrine, they plan to formally adopt it. However, when they return with a new collar, they find that another family has already adopted and taken Hana away.

Do Nishikata and Takagi end up together?

Their relationship deepens significantly during the summer vacation when they exchange mutual promises to make each other happy forever while watching festival fireworks, and a flash-forward reveals an adult version of the two with a daughter named Chi.

Who is Chi in the final scenes of the story?

Chi is the young daughter of adult Takagi and Nishikata. She appears alongside her parents in the post-credits scene while they participate together in the island's mushi okuri traditional event.

What is the significance of the mushi okuri event?

The mushi okuri serves as a recurring island tradition that brings characters together. Nishikata and Takagi fail to find fireflies during it earlier in the story, but successfully find them years later as adults with Chi.

Does Sanae leave the island for high school?

Although Mina and Yukari initially worry that Sanae aims to attend a high school in the city, they are eventually relieved to learn during the festival that she plans to stay on the island.