Taking place a year prior to the events of the Epilogue of Harry Potter and the Deathly Hallows, Harry's son James boards the Hogwarts Express on his way to begin his first year as a student at the famous school of magic. James is shy and nervous, deeply concerned about the tremendous Potter family legacy that he feels pressured to live up to. On the train, he makes two new friends: Zane Walker and Ralph Deedle. Both are Muggle-born, and Zane is an American, the son of a Hollywood movie producer temporarily living in Great Britain. Upon arriving at Hogwarts, James is sorted into Gryffindor, Zane is sorted into Ravenclaw, and Ralph into Slytherin.
Teddy Lupin invites James and Zane to join the Gremlins, a club of pranksters that includes himself, Lupin's friend Noah Metzker, and several other students from across Hogwarts' houses. The Gremlins sneak out of the castle through a secret passageway and play a prank, called "raising the wocket," on a Muggle farmer, who later reports that "Martians" have been stealing his tomatoes.

That year at Hogwarts, the school plays host to representatives from the American school of magic, Alma Aleron. These include students, representatives of the American Department of Magical Administration, and three teachers. These teachers are Professor Franklyn (who is actually Benjamin Franklin), Professor Jackson, and Madame Delacroix.

Like his father before him, James gets into much trouble, and gets entangled in a larger plot to destabilize the magical and non-magical worlds. This involves an organisation known as the Progressive Element, who wish to make the magical world known to the Muggles, and three relics which are believed to be able to bring Merlin to this day and age, at the Hall of Elders' Crossing.

What's it like to be the son of the most famous wizard of all time?

James Potter thinks he knows, but as he begins his own adventure at Hogwarts, he discovers just how much of a challenge it really is to live up to the legend of the great Harry Potter. As if it wasn't enough dealing with the delegates from the American wizarding school and figuring out the mysteriously polite Slytherins, James and his new friends, Ralph and Zane, begin to uncover a secret plot that could pit the Muggle and the Magical worlds against each other in all-out war.

Now, with the help of Ted Lupin and his band of merry mischief makers (The Gremlins), James must race to stop a war that could change the world forever his only hope is to learn the difference between being a hero and being the son of a hero.