After their final battle with the Utrom Shredder and saving the Multiverse from being destroyed, Mikey's been having horrible nightmares of unfamiliar battles and events. Then a malfunction with the Portal Stick sends them and Splinter to an alternate world where they meet their younger, stealthier counterparts, a Splinter who was/is Hamato Yoshi, a pair of teenagers named April and Casey, new mutants who are friend and foe, and a monstrous Shredder who's out for their heads. Starts in the '03 world and then goes to the 2012 world. The book is by: BrightLotusMoon, RyochanWolfgirl