: Premiered October 13, 2013. This season introduced the "A" plotline and the iconic fall of the prison.
The following shows aired their fourth seasons in 2013, often during the Fall premiere window: Season 42013
: The "gas-leak year" (the only season without creator Dan Harmon) premiered on February 7, 2013. : Premiered October 13, 2013
: The Season Four update (launched late 2013/early 2014) overhauled the jungle, introduced the "Trinket" system, and redefined the support role. : Premiered October 13