After centuries of remaining childless, Princess Celestia has an heir. Her son, Bronze Star, joins the Mane 6 and helps them keep Equestria safe from certain dangers. Along the way, he develops a strong romantic connection with one of the six mares.
Overtime, Bronze Star uncovers two plots. One of them involves his Aunt, Princess Luna. He learns that her spite and envy were not the only reasons why she became Nightmare Moon. Something far more diabolical and dangerous was responsible for her madness. Worst of all, she is still not safe from this evil.
The other plot concerns Princess Celestia. Bronze Star discovers that a group of political dissidents are conspiring to assassinate his mother. Motivated by his love for her and her reign, he vows to hunt the insurgents down and purge the threat they pose at any cost. Even if that means wiping out every last one of them in the process.