Eps.1-9 are quite a nice, likeable show, if you can stomach some unfortunate but harmless loli-pandering. ("Loli" = "lolita complex", i.e. the anime's occasionally being suggestive about sexual stuff with very, very underage girls. About ten or eleven years old. Nothing happens, but the show's still obviously winking to a segment of its audience that needs locking up.)
After that, though, eps.10-12 get enormously silly and can't be taken seriously at all. Intermittently, they might sometimes not be stupid. That's as good as it gets. Nothing bad is going to happen and you won't get arrested for watching it, but it's eye-rolling.
The show's hero is Kyou, who's theoretically in high school. I say "theoretically" because at the start of the show, he's a hikikomori. He almost never leaves his house. His classmates don't know what he looks like. He's pathetic. He spends all his time writing music and uploading it to the internet, after which his online collaborator, Kiriyume, will draw illustrations. (Theoretically he's a hikikomori because of a past trauma, but that's one of the more risible pseudo-traumas you'll see.) One day, though, Kyou gets an email from a fan who wants to meet him. He ties himself in knots wondering whether or not to accept, but eventually does and hangs around nervously in a park wondering whether or not to run away.
This fan turns out to be Jun, a tiny but musically gifted orphan who plays a mean guitar. (She's very shy, though.) Jun and her fellow orphans, Nozomi and Sora, drag Kyou back to their orphanage (a church) so that they can form a band. Kyou will write the music and the girls will perform. They've also got a deadline and a reason why this matters to them.
This is nice. Kyou tries to help the girls, but of course he's in no position to tell them to go to school and start talking to their fellow students. This becomes a growth experience for everyone. Even if I think Kyou's a twat for skipping school for months, I respect his courage in going back. There are other characters (Kyou's weird younger sister and a mildly tsundere classmate of Kyou's who also lives at the orphanage), but the band is where it's really at. The show takes it seriously. The girls can sing and play very well, but they've never done so in public and they've no idea about how to go about attracting an audience.
The loli jokes are there, but you won't burst a blood vessel. Kyou is annoyingly aware of sexiness potential in ten-year-olds, to a degree that might make you want to slap him. He'll overreact in semi-comedy fashion. (That said, though, he's not aroused by them or anything. Instead he'll be frightened that someone will see them, misunderstand the stupid things that these children can do and mistake Kyou for a paedophile.) Meanwhile there will occasionally be suggestive dialogue that's not what it sounds like and/or family-friendly shots of children in the bath. A normal viewer probably wouldn't realise that anyone could see dodginess here in the first place. That said, though, Kyou's sister Kurumi (also aged about ten) is mildly annoying in her clingy attachment to her big brother and tsundere-jealousy of other girls. "As a special rule, you're not allowed to get married."
The only thing I disliked here was the English Grandfather Episode (ep.6). The episode's theme is "putting feelings into words", which is expressed through both songwriting and the big question of "should you abandon your friends and go to live in England with grandad?" I dislike how it's handled. To me it felt shallow and clumsy, turning the characters into idiots for the sake of a badly explored issue. Practicalities are avoided, e.g. "can you speak English?"
After that, though, the show turns into harem nonsense. This is never great in any show, but here everyone's ages make it particularly unwelcome. Another little girl shows up, you see, and she's a prickly, high-handed bitch queen who'll announce that she's Kyou's wife. If he doesn't follow her orders to the letter, she'll assume that "I don't matter to you at all!" Admittedly she's had a semi-tragic upbringing that explains her inability to get along with people, but unfortunately that was silly too. Is this the 13th century? No. What a bunch of idiots. In short, she's an abrasive harem cliche and enough of a scene-stealer that she pulls the entire show into acting and thinking more as she does. Kurumi gets competitive. The girls go on "dates" with Kyou and so on. (At one point, Kyou admires his non-wife's decisiveness. That's one way of putting it.)
Mind you, it's so surreal that it's not offensive at all. It's just daft. Small children are acting like idiots, basically, and Kyou's enough of a wet noodle that he just humours them instead of telling them to stop being silly.
I liked this show best when it's about the music. That's how these fairly damaged people are helping each other move forward and heal. The overall theme is lonely people who lived in their own worlds and didn't know how to interact with others, I think, and it's nice to watch these people slowly realise that they don't have to be like that. I enjoyed this show. I'd even sort of recommend it, but you'll have to forgive some extreme silliness and it might be worth skipping the last three episodes. (Well, unless you enjoy shaking your head at a load of tripe.) Some people have called this show annoying and even shameful. I wouldn't even say that those people are wrong, but there's plenty of warmth in here too.