Sackboy and his new friends come together to defeat the evil Newton.
After the events of little big planet 2 you get sucked into a trans dimensional portal to meet Newton. After he gets possessed by the evil Titans you must travel across bunkum to revive bunkums 3 heroes: odd sock, toggle, and swoop. After that you must defeat Newton and the titans.
After a failed attempt to use the 3 titans of a planet in the known as Bunkum to make the planet more creative, Newton is turned into a evil version of himself, corrupted directly by the titans. Now, Sackboy and 3 of Bunkums old legends: Swoop, Toggle, and Oddsock must stop Newton and the three titans before they destroy the Imagisphere!