Quentin James is a student.
That is fairly normal, considering he is a 12-year-old boy. What is not usual, though, is that shortly after we meet him in the boarding school his parents left him in for very long periods of time between visits, he is suddenly whisked away from that facility to Edgewater, an extremely exclusive school. Attendence to Edgewater is by invitation only with one fascinating entrance requirement.
James is small for his age and extremely shy and introverted. At his old school he had no real friends to speak of and was always being left out of events. Case in point, right after we are introduced, we watch as a group of kid starting choosing side for a sporting game. Quentin was hoping to not be called last, as usual, but then it got even worse when he was not called at all.
When school break time came and the other kids were sent home for a week or two, James would find himself basically alone at the school; he was told his parents were always out somewhere 'making the world a safer place' instead of picking him up to spend time with them, leaving him alone with the caretaker grownups who had their own lives to worry about.
Then came the night he overhears a visiting adult tell Miss White, an instructor and really the closest person to James, that there was something up with his parents...something not good... and that James was "special ... really special. So special the Russians cannot have him, no one can. He belongs with us. It's a matter of national security." That was the night he was thrown into a waiting car and transferred to Edgewater.
Edgewater, we are soon shown, is a school for gifted youngsters whose entire purpose, other than standard school curriculum, was to train the next generation of spies for MI6. That entrance requirement mentioned before was a video game that was extremely popular but ridiculously difficult to ever actually defeat. It is involved finding hidden objects, breaking difficult codes, defeating super hard opponents and lots of other challenges. Only a handful of kids in all of the U.K. ever got to the end and most of them did so after failing several tasks - in other words, there were some successes but none perfectly. Until James.
So at Edgewater James will learn to hone his incredible skills while getting involved in actual cases (some of them without permission) and all the while trying to learn why his parents, who had vanished suddenly, were considered traitors.
Proving to be the key organization that James and his fellow students will have to contend with is I.O.N., the International Organization of Nexus. What Nexus means, well, that's kind of confusing, except that they are bad people. And defeating them is going to be a challenge. And after them, well, there are even worse things.