Angry Birds is one of the most successful video games in history, thanks to its low barrier of entry and addictive gameplay. But one question has never been definitively answered: why are the birds so angry in the first place? And what do they have against those green pigs?

The truth will finally be revealed in the upcoming CGI Angry Birds movie. IGN got a preview of the film and says the movie will be an origin story, detailing how exactly the birds and pigs came into conflict.

The movie takes place on Bird Island, where the flightless birds of the game (and now film) call home. It's a bit of a paradise. The birds know nothing of the outside world, and all the birds are generally carefree and easy-going.

All except for a few, that is. Red (the bird anybody who has ever played the game will instantly recognize) is the main character of the film and voiced by Jason Sudeikis. Red has anger issues and has to go to anger management classes. When the pigs arrive (the island's first visitors from the outside world), the majority of the birds seem to hit it off with them.

But Red doesn't trust them. He thinks the green pigs (voiced by Bill Hader and other various comedians) have hidden motives. That's all IGN would give away — but it seems safe to assume that Red and his angry friends will lead the charge when the pigs and birds come to blows. IGN reports the first teaser trailer for the film will drop next week.

Angry Birds will release in theaters on May 13, 2016. With an absurd amount of talent behind the project, it may just turn out to be a video game movie that isn't terrible.

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