The plot is that a con artist who is wanted to serve life in prison becomes a school teacher because of a bizarre turn of events. The principal hopes to use him to con his troubled students into behaving again. Heres a quick summary of facts for you -original idea -very funny -you will love the characters -jaw dropping surprise every chapter Heres how the plot line of each volume goes.1)Our teacher finds out about a student in trouble somehow or another.
2)He researches them
3)He works his way into their lifestyle (remember this is a professor and the students lifestyle involves things like robbery or crazy parties)
4)He uses his knowledge of the student to push them into doing a better job of whatever they are trying to do.
5)He blows it up in their faces
6)He picks up the pieces and uses it in a jaw dropping scheme to get them back on the right track.

As far as my character rating goes, they haven't really used a couple of the secondary main characters yet in any meaningful way. But other than that the characters are brilliant

As far as the art goes, Its great, just I have seen better. Not really a big factor in this kind of manga.

PS Don't watch the J-Drama version. It will disappoint and bore you to tears. Half the fun in this series is the reaction of the stunned students as to what is going on, the J-Drama can't express that and they make up a lot of bad story lines as well. The characters are completely without appeal as well.