The central story revolves around the main character, Sharaku-kun, and his "girlfriend" Wato-san, a tomboy. Sharaku-kun is, fortunately or unfortunately, a descendant of an ancient race of 3-eyed humans (yes, sounds like 3X3 Eyes, doesn't it?) who had once ruled the world with their technology and intelligence. His mother, a 3-eyes, had dropped him off at a doctor's residence, and had then been killed by a mysterious lightning blast. So the hapless doctor tried to raise the boy.
But Sharaku soon showed signs of not only being a super-genius, but an *evil* super-genius with mild psionic powers. With a combination of megalomania and pumped ego, he has the power and knowledge to destroy civilization. Except he has one fatal flaw: if his 3rd eye is covered, he becomes a clueless, cheerful, naive, crybaby, no-attention-span kid. And as a small, bald child, he looks like a Kindergartener, not the Junior High students he is.
His only friend is Wato-san, a daughter of a local priest, and a good aikidoist and karate-ist. Unfortunately, she tends to be gullible and a little bit of a 'screamer,' which might be understandable given the nasty graves and haunted ruins she often winds up in. She falls in love with Sharaku the megalomaniac, for when his 3rd eye is uncovered, he is forceful and brilliant, powerful --- and yet somehow lonely. Whenever she's in deep trouble, she takes off his bandage and has him rescue her. He, in turn, declares with characteristic selfishness that he's in love with her, and will turn her into his bride someday, to be the mother of future generations of 3-eyes. But, with his 3rd eye covered by a sticky bandage, he turns into the equivalent of a 3 year old, and Wato-san must look after him. Like a mother, she tends him, tries to keep him out of trouble, and heartily beats up anyone who abuses him --- she turns into his protector, as much as he turns into her protector when his powers are freed.
Unfortunately, little Sharaku must have his bandage on most of the time. In one story, his class is out on a fieldtrip to an old temple, where strange stones litter the area, relics from an ancient age. Sharaku, accidentally deprived of his 3rd-eye bandage, quickly learns their secrets: one contains a recipe, the other is the brewing device --- for a powerful mind-control potion that had been used to enslave people long ago. He explains this gleefully to Wato-san as he makes the potion, and then declares that he is going to go apply it first to his classmates, and then the rest of the world. "But I'll leave you alone, Wato-san, because I love you," he says as he smirks. Wato-san isn't about to let him enslave the world, however, so she leaps on him, pretends to kiss him, and slaps the bandage over his 3rd eye in his confusion. Sharaku drops his bottle of potion, and, with his eye covered, has no clue what was in it. Wato-san leads him off, laughing in relief.
In later books, Sharaku the child slowly begins to develop a mind --- not a sharp mind, by any stretch of the imagination --- under the patient guidance of Wato-san. He almost comes to regard her as his mother. Sharaku the genius sort of regards her that way, too, but he is always ready to push her aside to promote his evil schemes of world dominion. Yet, slowly, he begins to listen to her --- though he tries to ignore her whenever she disagrees with him --- and somehow, she always manages to slap the bandage over his 3rd eye whenever he really starts to get out of control.
The 8th book is somewhat disappointing; the latter half deals with Sharak and a 3-eyed girl who looks just like Wato-san, but isn't. It's not clear what happened to Wato-san, and the 3-eyed girl dies at the end. It's also not clear if there were any more stories beyond this one. Oh well; can't win them all :-)