s-CRY-ed, TV Tokyo/Animax
ANN; IMDb; Madman; Retro Junk; TV.com; TV Tropes; Wikipedia
The series is set 22 years after an environmental disaster that caused the Kanagawa Prefecture to split from the Japanese mainland. It's now officially called the Muraji Special Economic District, but more commonly known as the Lost Ground. This includes the city, which receives economic support from the mainland, and the undeveloped area, which is relatively poverty-stricken. Anyone who lives in the undeveloped area is called an "Inner." The disaster also caused about 2% of the people born since then to develop "Alter" powers (the number rises each year; at the time of the series, it's up to 5%), which vary greatly from Alter-user to Alter-user. But basically it's just the ability to manipulate (or create) the particles around them in one way or another, thus altering their bodies, or creating... well, any number of different sorts of things. This power is generally used as a weapon. Some Alter-users (mostly Inners) are called Native Alters, and the government doesn't seem to trust them. Sometimes with good reason; sometimes, apparently, just out of fear or prejudice.
One such Native Alter is a 16-year-old named Kazuma, who lives with a cute little girl named Kanami Yuta. She seems like a little sister, but actually they're just friends, orphans who formed a bond. Kanami works hard on a farm to earn money for them both, and also takes care of all the household duties. She's frequently upset with Kazuma for ditching work at the farm. (She also has dreams about the troubles Kazuma gets into, but isn't aware it's him in her dreams, at first.) ...While not working on the farm, he may just be goofing off, but more likely he's off doing mercenary work scrounged up for him by his friend Kunihiko Kimishima.
Anyway, there's this police force called HOLD, which exists to deal with Native Alters (many of whom use their alters to commit crimes, because of economic hardship or growing oppression by HOLD). Commander Martin Zigmarl, the first known Alter-user, and current head of HOLD, helped form a special unit called HOLY, made up entirely of Alter-users. This was supposed to be to help civilize Native Alters, and protect them, but it, like HOLD, has become oppressive toward powerless Inners and especially Native Alters. So, Kazuma ends up fighting against them. One of HOLY's Alter-users is Ryuhou, who forms a fierce rivalry with Kazuma. He is one of the strongest Alters in HOLY, but he has a very cold, formal disposition.
Other Alters in HOLY include Scheris Adjani, who has an unrequited love for Ryuhou; Straight Cougar, who's all about speed, and can be kind of annoying, but also funny (and serious, on occasion); Asuka Tachibana, one of the younger members of HOLY, and always worried he may fail; Urizane, whose alter involves watermelons; Elian, who can create electronic observation devices; and Unkei, whose alter affects reality by forcing people to act according to scripts he writes. There are others, but those seem to be the major ones. There is also a non-Alter, a scientist named Mimori Kiryu, who comes to the Lost Ground from the mainland. Her father is a major investor in HOLD. When she and Ryuhou were children, they became friends, and now that she's working with him, she wants to renew that friendship, but he isn't interested. Nevertheless, Scheris sometimes acts jealous of her. Also, Straight seems to be interested in Mimori, although she mostly finds him annoying, particularly because he always gets her name wrong (he calls her "Minori"; he also calls Kazuma "Kazuya"). Mimori is very idealistic, and sympathizes with the Native Alters, though she realizes this is at odds with her position at HOLY. She eventually gets in trouble for this, of course.
After awhile, Tachibana leaves HOLY. And at some point Mimori is arrested by HOLY or something, and Cougar saves her. He wants her to return to the mainland, but she doesn't. And at some point Kimishima was killed. Then Ryuhou and Kazuma had a really big battle that unleashed an energy (in an event later called the Second Uprising) that opened a doorway to another dimension, which the two of them entered briefly, and after that they were both lost for a time. Ryuhou had no memory of who he was or anything, and ended up freeing a group of Inners from a slave camp and from then on defending them against HOLY. He also befriended Kanami. Meanwhile, Kazuma was just off somewhere fighting in an arena. This lasted about eight months (which the series doesn't show us).
Eventually though, Kazuma encounters Mimori and Tachibana, who have been working together as smugglers, while they've both basically been in hiding from HOLY. Kazuma, Mimori and Tachibana soon hook up with Ryuhou and Kanami. Some HOLY members had been looking for Ryuhou, but even when he gets his memory back he refuses to return to HOLY. Scheris leaves HOLY as well, to stay with him, though he never seems to return her feelings, nor Mimori's. The group will sometimes receive assistance from Cougar, though they don't always want or appreciate it. There is also a new enemy, Kyouji Mujo, who comes from the mainland to take control of HOLD. There's this whole plotline about Alters being sent to the mainland to have their powers refined, which makes them stronger, but it's also bad. And it involves the other dimension, the source of Alter powers, and Mujo wants to use Kazuma and Ryuhou to open it again to increase his own power. Not everyone in HOLD seems particularly fond of Mujo, especially Zigmarl. But Ryuhou, Kazuma and the others especially hate him. And when he kidnaps Kanami, the two of them have to go to the city to rescue her and try to destroy him. Scheris and Cougar also help them. Meanwhile, Elian and Urizane basically watch and talk about everything that goes on, and often try to decide what side to fight on, or whether to just keep out of things. Eventually the Mainland sends reinforcements to fight Ryuhou and Kazuma, but the two have grown too powerful to stop.
The series ends with the two of them returning to their initial rivalry, to try to determine who is the strongest. Which seems kind of pointless and ill-advised, in my opinion. (It'd be a perfect time for the Mainland to strike again, when they're both drained from fighting each other.) But... I dunno, nothing really happens after the fight, it just ends. Kanami says some stuff, but it doesn't seem important or informative or anything. Whatever, anyway, not a bad series, I guess, but it all seems just as pointless as Kazuma and Ryuhou's fight.