It's based on a photo book, of all things. Here's a publicity release:

"On February 7th, it was announced that photographer Aoyama Yuki's popular photo book 'School Girl Complex' is going to be turned into a feature-length film starring the two young actresses Morikawa Aoi and Kadowaki Mugi. Aoyama has worked on many photo books for actresses and idols alike. He also did the cover shooting for the most recent issue of the beauty magazine 'anan' featuring AKB48's Kashiwagi Yuki. In 2010, he released a unique photo book titled 'School Girl Complex'. This photo book depicted all the (dangerous) charms of junior and senior high school girls from the point of view of a boy going through puberty. It was well-received not only by male buyers, but also from girls and women who gave it support and praise."

You'd never guess this film had an origin like that. The opening credit sequence avoids the girls' faces (like the photo book), but basically this felt to me like a normal film. It's quite good. It's set at the broadcasting club in a girls' school. They do school radio broadcasts and do rehearsals like a drama society, but in pairs on the roof. You and your partner sit in facing chairs. One person speaks and the other gives feedback.

There are four main characters. Two are nice, two are scary. The nice girls are the club president Manami Shintani (played by Aoi Morikawa) and her best friend Ai Morino (Maaya Kondou). The latter was my favourite character. She's friendly, straightforward and great to hang out with. Also, though, there's also Chiyuki Mitsuzuka (played by Mugi Kadowaki), who's a year older than everyone else since she had to repeat a school year. She's an intimidating femme fatale, if you like them sullen-looking. She's liable to make lesbian approaches on her classmates, only to say a moment later "don't worry, just joking". She's untrustworthy, but Shintani will take her seriously. (Meanwhile, Ai's never said how she feels.)

Finally, there's the aggressive, confrontational Kazumi Oda (played by Aoi Yoshikura) who always seems angry and keeps saying into people's faces what they've done wrong.

You probably have a fair idea about how this will play out... and you're not wrong. This film has no huge surprises, but it's still quite well done. I basically liked everyone, even the spikier characters. The love triangles are effective. The ending works. It won't change your life, but it's pretty good at what it does.