note: Captain Sugai-sama actually leaked this before it was announced during her radio show (she mentioned "taking a break from drama rehearsal" lol), but she covered it up quickly, despite that it was pretty obvious that something was going on.
Basic synopsis translation (thanks to kanjo of s48)
Translations and Transliterations from the official site and modelpress
21 high school girls are locked in a classroom.
Their only method of escape was to gather "likes" from their audience.
The story being told is one which takes place in the not so distant future.
The people of this time were so concerned with privacy, even students and teachers no longer revealed their names to each other. Female high school students experiencing school life in these circumstances were suddenly locked in a classroom! Their situation was being streamed in real time to the whole world, and an audience of complete strangers were watching through their tablets. The only method of escape was to gather many "likes" from this audience. To receive many likes, the girls acted in ways likely to gain the audience's attention, and the intensity of these activities quickly escalated. In this hidden away space, chaos erupts and girls who were backstabbed by the friends they trusted grew paranoid.
"Friends are important. But in this classroom, following the rules is most important"
What is waiting for those who disobey the rules? And why on earth have these girls been locked in here in the first place? Can these 21 girls who had their fates controlled by an audience escape without leaving anyone behind? An all-out mystery with concept and production by Akimoto Yasushi, staring all Keyakizaka46, begins.
-currently, it seems to only be a Kanji Keyaki drama, other than Neru, no other hiragana members have been shown.