What is going to happen in the movie Shrek 4?

There is no movie called "Shrek 4." The Shrek franchise currently consists of four films:

* Shrek (2001)

* Shrek 2 (2004)

* Shrek the Third (2007)

* Shrek Forever After (2010)

"Shrek Forever After" is considered the fourth and final film in the main Shrek series.

However, there are several other Shrek-related productions:

* Shrek the Halls (2007) - A holiday-themed television special.

* Puss in Boots (2011) - A spin-off movie focusing on the character Puss in Boots.

* Puss in Boots: The Last Wish (2022) - A sequel to the 2011 Puss in Boots movie.

Perhaps you are thinking of one of these other productions?