The era in which Harry Potter's parents lived in the Harry Potter series is known as the Marauders era.
The main characters include James Potter, Sirius Black, Remus Lupin, Peter Pettigrew, Lily Evans, Severus Snape, and others.
Now that the background has been covered, here is the synopsis.
1971.
The innocent young wizards cheerfully board the train bound for Hogwarts.
The Death Eaters are quietly growing in secret, and no one knows whether the people around them are friend or foe.
Voldemort's power will soon reach its peak, and Hogwarts will become the only truly safe place in the British wizarding world.
But there is no Chosen One favored by fate here, only an incompetent Ministry of Magic and an endless stream of ever-mounting crises.
The dark age is about to begin.