Now that Eustace has been introduced into the series and since all the Pevensies are done with Narnia, it's time for Eustace to show someone around. Namely, Jill Pole.
The beginning opens and issue of the day that C.S. Lewis felt he needed to address: Experiment Houses. They were apparently new types of "schools". The "teachers" supposedly let the children run around and do whatever they wanted because they were living experiments.
Of course Eustace's parents would have put him in something like that.
Jill is a victim of the bullies that rule the school, and Eustace finds her hiding from them. Not long after, they step into Narnia after asking Aslan to take them there.
They start off at an unknown location above Narnia in which they meet Aslan. He tells Jill six signs she needs to remember in the journey ahead.
Afterward, they are blown down to Narnia just in time for Eustace to see old King Caspian board the Dawn Treader for one last voyage to the Lone Islands to see if Aslan is there.
Unfortunately, Eustace being able to meet him before he left was the first sign.
There goes number one.
Then Eustace and Jill learn from a Parliament of owls that King Caspian's son Rilian disappeared several years earlier and hasn't been heard from since. He disappeared right after Caspian's wife, the star's daughter, died from the poison of a serpent. Apparently Rilian went hunting for the serpent, and after several trips, never returned.
Eustace and Jill then go off hunting for the prince, accompanied by Puddleglum, a marshwiggle (a half man, half frog). Puddleglum is probably Lewis' best character to date.
The journey north is intriguing and entertaining. There are several new features Lewis shows off in this book, mostly giant-related things.
While most people believe that the emerald witch who is the villain is Jadis reincarnated, I don't believe so.
This is easily the third best of the series because of the interesting end.