Umika Konohoshi is a shy girl who has trouble talking to others, and dreams of making friends in outer space. On the first day of high school, she meets Yu, who claims to be an alien, and one who can read minds with telepathy!

Umika is excited to start building a rocket with Yu. However, she is then confronted by her classmate, Haruno, who just happened to spot Umika and Yu sneaking into a lighthouse after school...

In their quest to build a rocket, Umika and her friends decide to visit Matataki, their classmate who is a skilled engineer, but doesn't attend classes. However, they soon find out that this mechanic's got one short fuse!

Haruno shows up with a surprise for Umika and Yu. The three of them prepare to face off against Matataki in a bottle rocket duel. The fate of Umika's rocketry dreams hangs in the balance!

Matataki convinces Umika and the others to start a school-sanctioned club to finance their rocketry endeavors. The next day, everyone in Umika's grade sets off on an overnight study camp.

Matataki gives the others a crash course in model rocket building. Some time later, Umika and her friends attend a model rocketry festival, and run into a familiar face...

With both summer vacation and the regional qualifiers for the Model Rocket Championship drawing ever closer, tensions run high between Matataki and the rest of the group.

The Model Rocket Championship regional qualifiers have finally begun. Umika is struck with fear right before her speech in front of a crowd. Can she manage to pull herself together in time?

With summer vacation over, Umika must put on a brave face in front of the others after their loss. She soon learns that Matataki refuses to talk to anyone or come to school.

With Matataki still absent from school and shutting everyone out, Umika must find a way to get through to her. But first, they decide to enlist help from a familiar face...

Umika finds herself sick and bedridden. Yu, Haruno, and Matataki decide to pay her a visit, much to the surprise of Umika's sister, Honami.