White Tower represents doom for those who have tried to use magic over the years. Once magic was taught in the Five Kingdoms but then people thought that it was a wild thing for them and they completely banished it from the land. After that day those who practice magic are considered sinners and are sent to the White Tower which becomes their final resting place. No one has ever come out of the tower once he is thrown into it but the time has come to utilize magic once again.
Then there is Ferrin in the story who is committed to making a way out for himself and others out of the White Tower. If he succeeds then the magicians would be able to reign on the land once again. War as serious as that seen in Plague of Shadows and Rockslide is approaching the kingdom and the only way to keep the balance is to use magic for the defense purpose. If humanity does not play sensibly this time then the days to rule the land are over forever.
Tim Gerard Reynolds is considered a legendary narrator for such stories thus there is no need to criticize the narration. There is more than one primary character in the story so don’t go anywhere until the story is told fully.