Four young stallions decide to form Equestria's very first thrash metal band. Loud, aggressive, and powerful; it is a style of music nopony in the world has ever experienced before. Within weeks, their popularity begins to soar, the heavy riffs and rebellious lyrics apparently striking a chord with their audiences, and soon they become one of the most popular musical acts in Equestria.

However, their incredible success is accompanied by unforeseen perils: greed, arrogance, excessive lifestyle, tensions between friends and loved ones, not to mention the ugly depths of the whole music industry. Powerful figures begin to emerge, their curiosity piqued by the band's "miraculous" rise to fame and fortune, trying to find some sort of hidden power that is at work behind the music.

What does it look like when four youngsters are "living the dream" without any kind of restraint? How do they cope with being caught up in some power struggle behind the scenes, let alone being on tour? What is the secret of their success? What future does it have in store for them, and for all of Equestria?

This is the story of Metallicolt...

(MLP meets Metallica)