When George quits his job in a huff and later regrets his decision, he tries to act as if nothing happened but ends up getting humiliated and decides to get back at his arrogant boss. Jerry also tries to get revenge on his laundromat who allegedly stole $1500. This episode effectively divides itself into the George/ Elaine and Jerry/Kramer saga and it's proved how naturally they can work with each other and as of this episode; the show becomes less about Jerry's comedic mishaps and more about the wacky adventures faced by the whole gang.
While George's plot is great and Alexander is at his best (especially whilst quitting), the plot itself doesn't really work; George is getting revenge on someone just because he didn't forget that George quit on him and this whole "mickey" thing is such a random way to punish someone; i agree with Elaine when she says "wouldn't it be easier just to punch him in the nose?"
Another plot - related mistake is the whole Newman story; it just doesn't belong here and doesn't even classify as a plot since the whole thing is told through Kramer and not seen.
Aside from this though, the episode is hilarious and the awesome foursome all walk away with plenty of laughs under their belt but Kramer even moreso.
Sometimes the humour relies on cultural references and as this was over 10 years ago a lot of them don't make sense to contemporary audiences but if you have the allusions section on this website at the ready then you should be fine.
The Revenge is a very, very good episode of Seinfeld but it's massive plot holes deem it a missed opportunity.