After having moved away several years earlier, Saku Oyagi returns to his hometown to begin his high school life. Saku has always enjoyed simply staying home and reading books, but his childhood friend Mihoshi Akeno used to forcibly take him outside to take part in various activities. On their last day together, Mihoshi fell out of a tree, causing Saku to go to the hospital with a broken arm, and since then Saku has never wanted to see Mihoshi again. However on his first day at high school, he meets Mihoshi as she is trying to recruit members into the astronomy club. Saku attempts to avoid her as well he can, but after Saku realizes that the reason Mihoshi did not see him off years ago was because she too was in the hospital, Saku makes up with Mihoshi, and joins the astronomy club.

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.

The astronomy club members wake up late the next morning and first spend some time warming up in the outdoor baths. Ayumi Omi notices Roma stressing over studying for university entrance exams, and takes him to buy a study book and then have dinner at a fancy restaurant. The astronomy club members wait until the moon sets on the third night and spend their final night in the mountains stargazing and taking photos. The members use some eyepieces Mihoshi brought to find Saturn, which is an entrancing sight for everyone. The following spring, Mihoshi has succeeded as club president after Roma graduated and entered into university with Ayumi. Everyone puts in more effort this year for recruiting members, since they are now one member short, and are again in danger of getting disbanded.

DVD 5 Special.