| Spoiler warning!|
This article contains plot details about an upcoming episode.
The release date and the price is currently unknown, but it is likely to be released on Steam. It is said to be about 3 times bigger than Fleeing the Complex. Henry, Ellie, and Charles are also confirmed to appear in the game.
The game will take place after the events of Fleeing the Complex.
The Toppat Clan are likely to appear as a possible main antagonist, however, this has yet to be confirmed. It is currently unknown who the other characters will be if they are other characters.
Series' creator Puffballs United announced that a sixth installment was coming on November 22, 2016 in a news post on Newgrounds. He revealed that the game will be "huge" and will take more than one year to come out. He also said that Ellie will return as a character. 
On January 5, 2017 he officially announced that he started working on the sixth game. He said that the game will be the final game in the Henry Stickmin series and that it will be at least "3 times bigger than Fleeing the Complex". Unlike all the other games in the series the sixth game will not be a free online Flash game, instead it will likely be released on PC platform Steam along with remastered versions of all the other Henry Stickmin games as part of the The Henry Stickmin Collection. 
On December 12, 2017 he revealed a bit of an image which would later be revealed on January 3, 2018. The same day, the acronym for the game was revealed to be CtM.  The picture has a same look to the post back in December 12, 2017.
On May 22, 2018, PuffballsUnited revealed the full title of the game: Completing the Mission.