Sou, a member of the Astronomy Club, finds his ordinary high school life turned suddenly upside down.

The Astronomy Club gang tries to make Yui feel welcome following her sudden and mysterious appearance. She struggles to understand what she's doing at Uchihama Academy.

Airi reminisces about meeting Sou and Kaori; the Astronomy Club tackles the Judo and Karate Club dispute, with different results, and they make headway on the case of the school ghost.

Sou spends time with his new camera; using the fine weather as an excuse, the Astronomy skips classes to go for a picnic, but they miss their bus stop.

A lecture on quantum theory and Schrödinger's cat threatens to put the kids to sleep; the Astronomy Club tries to get to the bottom of the Computer Club's oddly low-tech school festival project.

The members of the Astronomy Club discuss their futures and what career paths they'll follow after high school, but Sou discovers that an arranged marriage looms over Nagisa's head.