As with the opening, the book plays out exactly like the movie with Tommy attempting to get the local authorities to believe Jason is back. The only person who actually believes him is the sheriff's daughter Megan, who helps him escape jail and together, they confront Jason at the Forest Green Lake (Camp Crystal Lake).
The author, Simon Hawke, gives us a glimpse at Jason's childhood. Unlike the films, he's never referred to as being deformed, but instead he was a silent child who was bullied at school and at Camp Crystal Lake.
Sheriff Michael Garris is given a little bit of a backstory, a widowed Vietnam veteran who's doing his best to raise his teenage daughter, Megan. In the film, the character comes off as an idiot but he's better written in the novelization.
The biggest change is the ending, where Jason's mask floats to the top of the lake. Later, Mr. Voorhees is visiting Eternal Rest Cemetery, only to learn his son has risen from the grave. Jason's father has never appeared on-screen. The ending with Jason's mask was filmed but wasn't used in the movie. Mr. Voorhees's ending was planned but never filmed, which is sad, as I would've liked to have seen it.
Overall, Jason Lives: Friday the 13th Part VI is a must-read for any Friday the 13th fan - if you can get your hands on a copy.