The "Harry Potter" films generated 7.7 billion dollars in box office worldwide. "The Lord of the Rings" series made some 2.9 billion, and this year's Oscar Best Picture "Life of Pi" has taken in 608 million since last September.

It looks like young heroes are not only saviors of the world, but also box office hits.

Indeed, one of the hottest film genres in Hollywood is always hero-themed movies. People could always learn more from these young heroes -- a journey from being an ordinary child to a brave hero tells us to never look down on anyone, including yourself.

From "The Spiderman" to "Harry Potter," from "Eragon" to "The Lord of the Rings," though these hero-themed films always bring similar story plots, audiences are still attracted, because they can always relate themselves to the young heroes in the films, who are just like anyone around us.

This summer, another young hero film, "Percy Jackson and the Sea of Monster," is expected to attract millions of moviegoers. Based on the true situation of the novel writer's son -- who is suffering from dyslexia and attention deficit-hyperactivity disorder (ADHD) -- the film will continue the adventure journey of Percy, son of God of Ocean in Greek myths, in his search for Golden Fleece.

In 2010, 20th Century Fox turned the first novel of the "Percy Jackson" series into movie, which made 226.5 million dollars worldwide. Compared to the gross revenues of the eight-film franchise "Harry Potter" and the three-film franchise "The Lord of The Rings," it is relatively small.

However, the film provoked strong reactions from audiences, especially children and parents who are struggling with dyslexia and ADHD.

Rick Riordan, author of the Percy Jackson series of novels, told the press that he received a great number of emails and letters from families who have children who are ADHD or dyslexic patients. Some children used to be ashamed that they have dyslexia, but now they feel different about themselves.

Haley, the son of Riordan, said: "You read a lot of books and none of them have a hero who is dyslexic or has ADHD. It's always perfect people in a perfect world doing perfect things. Percy is, in fact, very flawed and he has to fight against that and at the same time fight monsters."

Percy is a person unlikely to become a superhero. He grows up with a single mom, has dyslexia and ADHD, has never scored above a grade C and considers himself as a loser until he discovers that he is actually the son of Poseidon, the God of Ocean, which he once thought only existed in mythology. This leads his life to another path. He finds that his difficulties are not a weakness at all, but a sign of greatness. Percy steps into an unknown world, where he learns to battle with all kinds of different obstacles along the journey and grows up to be a young hero.

"This movie (the new one coming in August) starts off where Percy has a lot of self doubt and he is not really a hero anymore, " Logan Lerman, who plays Percy, told Xinhua.

Lerman said that in this movie all the attention is shifted to Clarisse, another demi god, and Percy is a little bit "insecure."

This is the part of Percy that makes audience easy to relate themselves to the character.

"I think everyone is experiencing in this film like self doubt, " Lerman said. "I always feel very insecure, and through that anxiety and all the stress I feel, it's almost like feel the fire to try to discover what I need to discover."

Besides, friendship and brotherhood are also key elements in the film. Percy's reunion with his two demi-god friends, Annabeth and Grove, and his one-eye half brother Tyson add much flavor to the coming film.

"The reason I did this one was really the brother theme, the idea of Percy learns he has a Cyclops brother and how he deals with that," Director Thor Freudenthal said. "And his reluctance of embracing the brother, and then once he does, it's kind of tremendous."

The countless sea monsters, ghost-driven cabs and a mysterious unknown world in the film may be exciting enough for audiences, but what truly will move them is probably the process of a child growing up to become a hero.

Just like Lerman said: "You will realize your own potential, and have confidence in yourself as well."