[asaqe]

Originally Posted by xizro345

While not exactly stellar in story, at least it's fun. I liked the fact that Chieri got parts in which she acted like a fool, in contrast with her usual behavior.

Spoiler for Recap of the Drama CD for those interested:

It's 40 mins long (two 20 mins segments), the setting is not completely clear, but looks to be early in the series (Mimori hasn't got the Mariko name yet, there's a bit of explanation on WOTAs made like the other characters don't really know much about them).

After a live in which Mayuyu saved the day, the kenkyusei discuss about her. There's genuine curiosity about who is she. A normal person? A Cyborg? A Robot ("an android" as Suzuko constantly corrects, this becomes a recurring gag in the whole drama)? Eventually, the curiosity gets the better of them, with Nagisa being the only one not completely sure about it, and they start to follow Mayuyu to discover more. The early attempts don't really work (especially Chieri manages to look like a fool), so later they settle to follow Yukirin, since she's probably the closest person to Mayuyu. After catching her discussing something with someone calling herself "Black Snow", the group manages to hear Mayuyu and Yukiririn talk. Aside the usual "quotes out of context", a sneak peek shows apparently that their worst suspicions are true, making them flee in terror. Yukirin seemingly notices them but all she does is laugh maniacally...

The following day people are still unsure on what to do, and what they've seen means. Mayuyu shows up, but she doesn't look well and eats far less than usual. Another "investigation" starts, and the group hear Yukirin again calling someone with the nickname "Black Snow". Kanata, suspicious as ever, suggests that Yukirin is in reality a DES spy, and the reasoning triggers a spree of paranoia. Starting from the idea that Mayuyu has been "substituted", the girls really go overboard, scrutinizing every minor detail of others to confirm if people are real or not. Only Nagisa tries desperately to calm the group, with little success, at least for a while (among others, I think Chieri's reaction is funny).
Later, Mayuyu collapses due to no apparent reason and it's brought to her room. Going there, they hear Yukirin's voice. With an increasing megalomaniac voice, Yukirin says Mayuyu has become a "Dark Soldier" ("Yukirin is really a bad person then", is Sonata's comment). The development is too much for Nagisa, who decides to enter the room and implore Yukirin to stop doing this to Mayuyu. Since her secret is out, Yukirin orders Mayuyu to "dispose" of the kenkyusei.... And it turns out it was all a ruse.
They were just practicing for a movie, "Idol Cyborg Mayuyun" in which Mayuyu plays the good guy and Yukirin the bad guy ("Black Snow"). Seeing the group there, they decided to use it for reharsal. Yukirin was simply trying her part alone when Nagisa and the others saw her, and they mistook completely what she was doing. The earlier discovery made on the group was on set as well. Given the schedule, it was pretty tiring for Mayuyu (hence the reason she didn't feel well).
Mayuyu thanks everyone for being worried about her, but the entire group runs away, very embarassed.
Despite all the ruckus, they're glad Mayuyu wasn't an android...Or was it? Mayuyu later mentions her fever and not feeling well was due to her overheating, and she discusses with Yukirin how she inherited the the original Mayuyu's soul.

Spoiler for Mayuyu:

I think she is literally the original Mayuyu with every upgraded model adapting to her original personality since a common issue with cybernetics is you will never really get used to your synthetic parts. So her brain literally overheats when she tries to reconnect with her past self