The Turtles come face-to-face with a territorial new group: the Punk Frogs! As the two sides battle across Mutant Town, fresh and familiar enemies make their own devious moves. The Utroms and Triceratons have returned, and their tensions are at a breaking point! Plus, a strange doctor approaches the Turtles with an offer they can't easily refuse.

Then, get ready for the Armageddon Game in the prelude stories Opening Moves and the 2021 Annual, "The King's Gambit." For millennia, the Pantheon family have played a deadly chess game with humanity in their twisted pursuit of victory. But now, the Rat King sees the opportunity to end the eternal contest once and for all: a final, crushing triumph over his immortal siblings and all of humankind and mutantkind alike. It will be up to the Shredder to find a way to stop the trickster god and his new trio of terror--Madame Null, Baxter Stockman, and LeatherKrang! Will the former master of the Foot Clan be able to locate the necessary pieces to foil the Rat King's latest deadly gambit, or will chaos rule the day in NYC and Mutant Town? One thing's for certain: The answers won't be found in only one dimension.

Volume 16 includes Teenage Mutant Ninja Turtles issues #125-132, the 2021 Annual, and The Armageddon Game: Opening Moves #1-2.