Lots of brotherly love, a bit of a coming-of-age story, and some comic-book violence.
Note: This is a movie tie-in manga-style comic book. Some elements vary from the film. (Note also that this book is to be read right to left.)
Hiro Hamada is a fourteen-year-old genius, college student, and inventor. Though he might not say it out loud, he adores his older brother, Tadashi, who is himself a genius inventor with a passion to look after others' well-being. Hiro needs no one but Tadashi... until Tadashi is suddenly sucked into a portal, leaving Hiro with a robot named Baymax, his own college friends, and a masked man who needs to be stopped.
Hiro is by no means a perfect boy. He can be rude (though sometimes unintentionally) and has flashes of temper. Though his relationship with Tadashi is strong, it is, at times, to his own detriment as he refuses to believe he needs anyone else. His poor actions, while lighthearted at times and perhaps understandable in others, are clearly negative; his right decisions are applauded as such and he does improve.
On the other hand, Tadashi is always thinking about others, whether it's helping with a scraped knee or trying to help Hiro become his own man. He is not without flaws, however. He loses his temper with Hiro a couple times (though understandably) and takes the blame for something he did not do just to protect his brother.
Tadashi's friends (whom Hiro later accepts) are a supportive group. Healthcare bot Baymax performs his functions as he ought.
Both Tadashi and GoGo Tomago strike Hiro, though only one is in anger.
Hiro makes classroom chairs fly, causing chaos, but no damage. His microbots, designed for rescue purposes, are used three times in destructive ways; two characters are noticeably hurt, though not beyond scratches and scrapes.
Drug and Alcohol Content
A couple female characters wear very short skirts.
Crude or Profane Language or Content
If you're like me and can't get enough of Disney's take on Big Hero 6 (and specifically of the Hamada brothers), this manga comic will give you more of Hiro and Tadashi. As the book is not entirely faithful to the film, it's a semi-new story with extra character-building. While not all character actions should be mimicked, many of the values brought out are great.