The Goon goes to the dentist and finds out that the receptionist has been replaced by a sentient manatee! And the Goon hates manatees! So he punches it! The dentist doesn't like that so he kicks Goon out. Leaving him with the dilemma of how to eat candy apples with a sore tooth. Then aliens show up.
Not actual synopsis. (But that is the actual cover, so who the $@#%* knows?)
"If this is your first time [reading The Goon], you are in for a treat -- if not, you already know how lucky you are." -David Fincher, Filmmaker (The Curious Case of Benjamin Button, Fight Club)