The new semester starts and on the bus to school Saku notices a tall man also getting off at the school. During the welcome back ceremony, the man that Saku saw earlier is introduced as a new teacher named Nozomu Soma who is in charge of Saku's class and world history. Mihoshi calls him "So-nii" in front of everyone and rumors abound as to what their relationship is. Later, Soma becomes the astronomy club's adviser and he explains to the others how Mihoshi's father was his professor at college and also the club adviser for their astronomy club. Soma wants the club to do a planetarium for the upcoming cultural festival and they get in the top three in a popularity contest in exhibits, the club will get more funding. Saku becomes annoyed at Mihoshi's and Soma's relationship and is approached by Fumie to help with the literature club.
Saku Oyagi returns to his old hometown in order to start school at Soei High School. On the first day, he runs into an old childhood friend: a second year named Mihoshi Akeno. As children, the two used to play together, with Mihoshi, or Mii-chan, being extremely fond of astronomy. After convincing Saku to join the school's astronomy club, another girl, Hime Makita, joins the club in hopes of winning over Saku. This is the story of the 6 club members of the Soei High School Astronomy Club as they soar through their lives, each maturing and changing their outlooks on life.
