Danganronpa: Trigger Happy Havoc puts you in control Makoto, a kid who has been invited to join Hope's Peak Academy. This school is known primarily for one thing - only enlisting the best of the best. In fact, each student is considered the "ultimate" in one field or another. One girl is the lead singer of the most popular band, while another is world renown for her poetry. One boy is considered the ultimate baseball player, while another writes the best fan fiction and another has the strongest moral compass. So what makes Makoto so special? Well, he is average, average in every respect except that he was picked in a lottery to join and thus labeled the "Ultimate Lucky Student."
Makoto's schooling doesn't start off that well, though. As soon as he walks through the front doors, he collapses and when he comes to, he finds himself alone in a classroom. After making his way to a common room where he meets his fellow ultimate students, they are are all presented with an odd situation. A strange teddy bear appears and tells them that they are all prisoners and the only way to actually graduate from the academy is to murder another student and not be found out.
When you take away the odd Japanese wrappings that Danganronpa swaddles itself in, the game becomes essentially a Phoenix Wright-like trial game, or even something similar to Telltale's Law & Order series. When a murder occurs, you start interviewing your fellow students and looking into anything that seems out of place. The surviving students get together and try to sleuth out who the killer was. If the correct culprit is chosen, then he or she is executed in a manner appropriate for that student. If, on the other hand, the wrong person is accused - then the killer walks away and everyone else dies.
The story of Trigger Happy Havoc does run a little deeper than that, since your goal is to not only uncover the murders amongst your classmates, but also determine just what is going on in Hope's Peak Academy and who is manipulating everyone.