It's about a sex-obsessed schoolboy surrounded by hot girls. (The only other named male character is gay and in love with him, but on the other hand there are also lots of predatory lesbians.) It's also full of nudity. Two TV networks pulled it from their schedules before broadcast and the original TV episodes sometimes hide half the screen with censor steam, while the uncensored DVD episodes are a nipple-fest.
It's also quite good. It's silly and I wasn't a fan of the show's romantic choices, but the premise justifies the absurdities and the dramatic finale works.
TAKETO AKUTAGAWA is a bestselling genius porn author. He's prone to uncontrollable lewd fantasies, extreme overreactions to anything and to writing his porn on any available surface. However, he's also a good-natured schoolboy with no sexual experience. He's nice (although the girls in his class all assume that he's a slavering beast). He also works for the school newspaper, which means he's always working on another article for them and being ordered around by the newspaper's slavedriving lesbian editor. The show's first episode hits Taketo with so much undeserved punishment in ep.1 that it's as if the production staff assumed we'd all hate him and was trying to pre-empt this by making the universe hate him too.
Also, he goes to Genius School. Everyone on campus is a genius at something, which in the case of Tsukuru Kagaku means "mad scientist who's liable to invent and test new heat-seeking missiles". The school regards itself as a petri dish for the future, so they don't apply normal standards of decorum and discipline. In other words, the show has a licence to go nuts and it'll fit the setting.
The first pleasant surprise is that even though this is a light novel adaptation, hardly anyone in the cast is in love with him! Over the course of the series, Taketo's reputation rises from "officer, arrest this sleazebag" to "probably sort of okay but still a porn peddler". Considering specific characters...
UTAE SONOKOE is a genius pop idol. When Taketo helps her in ep.2 (thanks to some unconvincing leaps of logic), she falls in love with him. She admires his pornography, calling it art that speaks to the human condition, and she's probably the only girl with whom Taketo can be completely honest about himself. She's nice, generous and has big boobs. I admire her decisions in ep.12, helping her love rival even in full knowledge of what she's doing. She's the most popular girl in school and everyone adores her. Taketo will never find anyone else like Utae and I was reeling in disbelief that the anime was cheerleading for a different First Girl (although Utae's the official second place rival). If you don't believe me, look at who's featured most in the title sequence.
FUKUNE NARUKARA is a genius clarinetist and the official First Girl. I don't hate Fukune. She's nice enough and she gets a character arc that pays off in ep.12. She is, though, basically a robot. She doesn't really understand human interactions and it's hard to be sure whether or not she has feelings for Taketo at all. She's passive and neutral in her relationships with him, whereas Utae knows what she wants and is active in trying to achieve it.
Furthermore, Fukune is being presented as immature. Her figure and personality suggest a young child, despite being in the same year as lots of horny teenagers. She doesn't understand sexual references. For her to win the romantic race would mean giving victory to someone who wasn't trying and who probably shouldn't be imagined in a sexual context anyway.
There's nothing wrong with the character, mind you. I like her. Her backstory explains everything (especially her father) and her character journey is a story worth telling. I was, though, cheerleading for Utae.
Of the other characters, I liked Raika Meiki. She's a genius photographer who's obsessed with ugliness and regularly berates Taketo for being insufficiently depraved and repellent. Because of this, she becomes the person he can talk to the most straightforwardly. Underneath, she's extremely messed up. (See ep.5.) Ritsu Enshuu, though, is a one-joke character and extremely repetitive. Oh, and Kurumi Kuroki might be an alien, an immortal and/or a ghost.
Theoretically, I like this show. In practice, its silliness sometimes gets a bit much. I disliked ep.7, in which Taketo is ordered to wear an invisible stealth suit and infiltrate the girls' dormitories. No, stop it. Get out. (I liked the scene with Raika at the end, though.) Similarly, I recoiled from the bit in ep.9 where our heroes sneak up on someone by shuffling along under cardboard boxes with eye holes cut in the front. They're outside, in full daylight, with nothing else in sight. Piss off.
Sometimes, all this works. I think ep.5 gets away with its silliness (e.g. lesbian bikini wrestling duels), because the episode's so very, very bonkers. The show's a lot better than you'd expect. But it's still a very uneven ride, with some decisions I strongly disagreed with.