Kana Koumoto - a cheerful 17 year old who can often be a klutz and nosey. One day, while hanging out with her besties (Pets, Mossan and Hijiri), Mossan starts making a rocket using empty soda bottles.

One morning, Kana and her besties witness Hijiri kissing a college student Toshio inside his car. Acting more mature than any of her classmates, Hijiri suggests Kana and her besties to do a photo shoot with Toshio.

Mossan is the most mature of all 4. With a passion of becoming a designer, she has been working outside of school. Upon discovering her working towards a fashion contest, Kana feels the urge to help her, which rubs her the wrong way.

One hot summer day, the 4 girls and Haruko are playing in the pool. They notice that Pets is missing. Kana later hears from her classmate Aida that Pet's family is very rich and they are moving to Mars.

Depressed, Kana flips over the collection of photos she took with her besties. The next day, the 3 girls gather by the beach as they watch the rocket Pets is supposed to be on.