One of the crucial things is how slowly it moves. We are used to stories of superheroes moving fast enough that five significant things can happen in the twenty-something pages of the average comic. The first eleven episodes of the new US TV show Heroes, though, are gently paced even by the standards of episodic television; by the half-way mark of the first season, we are little closer to understanding what is going on and a very long way from forming a superhero team or dealing with the atomic explosion that will soon destroy New York. Several of the characters haven't even fully accepted that they have powers, let alone got a proper handle on what they are or how they work.

Heroes is a genuine serial in that it deals with the slow accumulation of knowledge among the characters and in the audience, episode by episode. We remember individual episodes as much for what we find out as for what happens—there was, after all, a time when we thought that the preternaturally persuasive Eden was just a helpful neighbour or that Sylar was just an ordinary brain-eating serial killer. Heroes is also a show which takes the time to see its characters in the round, with all their moral ambiguity and mixed values—a decision that Eden makes in the last seconds of her life turns around everything we have thought about her, and leaves us with an indelible impression of someone smart and resourceful enough to make a right choice when she seems to have no choices left.

Episodic television is on one level all about making the audience watch next week, partly for the thrills and spills, and partly for the people. Making us fall in love with characters is hardly something original to Heroes—one might argue, indeed, that the real originality rests in a show like the new Battlestar Galactica where it is fairly hard to like any of the variously deranged religious fanatics that populate it, yet we remain fascinated. What Heroes does, though, is create several characters whom we start off liking, and love more the more we see them, while allowing them to be largely ineffectual, at least for the moment.

It seems likely, for example, that Peter Petrelli will end up becoming something close to a team leader, but rarely has there been such unpromising leadership material. He is a neurotic New Yorker, trapped in the shadow of his corrupt politician brother and a father badly in hock to the Mob; he is a competent male nurse, who overinvests in his dying patients and has fallen in love inappropriately with the daughter of one of them. He is only just starting to understand what his powers are—and misunderstanding them has taken him closer to self-destruction than is quite sane or comfortable. What he has, though, is a sense that it is important to try to do the right thing, and it is this sense of right action, without the safety net of clear knowledge, that is a significant part of Heroes's mission statement.

Even more than in Peter, of course, this philosophy is embodied by the show's most attractive character, the chubby Japanese nerd Hiro. Peter, though, has had to work it out for himself, whereas as soon as Hiro learns that he can bend space and time around himself, he draws on a moral framework gained from his long-standing fascination with comic books. When he uses his powers to cheat at cards, he expects it to go wrong because he knows from comics that personal gain should form no part of the hero's journey; he feels guilt when he tries and fails to save people as much as joy when he tries and succeeds.

He also has a gift for friendship; part of the charm of Hiro is his utter and reciprocated devotion to his best friend Ando, but another part is the way that he manages to charm everyone he meets, even Peter's cynical brother Nathan. Hiro is also the focus for many of the show's sheerly fannish pleasures. When, at the end of the first episode, he finds that he has teleported himself from a Japanse commuter train to the middle of Times Square, we feel a surge of utter joy as he waves his hands in the air and shouts "Hallo New York!"—a surge that we feel all over again when Hiro finds the scene duplicated in a comic book.

One of the reasons that Heroes works is that it never neglects the pragmatically real; Hiro has to steal the prophetic comic book—and, with Ando, later cheat at roulette and cards—because he is in a foreign country without money, and Nathan is worried about the effect on the electorate should they ever believe that a candidate can fly. Part of learning to be heroes is acting in completely non-heroic ways—the geneticist Mohinder gets fed up trying to prove his murdered father's belief in mutants true and goes back to India for several episodes. (This is also, we may as well point out, a mainstream American show, several of whose characters are not white, or American.)

What then is there not to like? Blandly menacing as Mr. Bennett, the man who is trying to put a lid on all this, is, he is too much a default setting for this sort of plot—his reaction to the fact that his cheerleader adopted daughter can regenerate is to try to steal her memories as a way of keeping her safe. The cheerleader Claire is also one of too many women in peril, only one of whom, the bad girl Nikki/Jessica, sex worker with a super-strong murderess for a split personality, has much chance of doing things for themselves. But for the most part Heroes is glorious touching fun and we can hope that in these respects as in others, the creators have thought of ways for it to be better.

Roz Kaveney is a writer and reviewer living in London. Her books include Reading the Vampire Slayer, From Alien to The Matrix, and Teen Dreams; Superheroes! will be published in 2007.