The 4th and final part kicks off with Raph having a happy mood for the rest of the day(Happy by Pharrell Williams).Later,Splinter and Sora meditate quietly in the dojo but he’s interrupted by the turtles and Po making a mess and skateboarding in the lair (again). Sora scolds them and tells them to keep the volume down so she and Splinter could meditate but then she askes them what are they doing, Mantis informs her that Mikey is teaching Po how to skateboard then he accidentally runs over the 3 kids over while in the process.
In the Shredders lair, Shredder is impressed of Tai Lungs respect and tells him that one of Shifu's female students had a daughter and orders him to destroy her and her friend which Tai Lung agrees.At the surface, Crane and Leo-Angelo stand on a roof top showing him how to use his new jetpack as wings (Put One Foot In Front of the Other from Santa Claus is Commin’ to Town).
Meanwhile, the other warroirs fight off Foot Soldiers. However, the Purple Dragons, kidnaps Shifu, intending to hold him for ransom to his students but when they turns, the Turtles and the Furious Five are already gone. Back at the lair, the warroirs humbled at Shifus kiddnapping Splinter then decides that the time to hide is over, and the Turtles and the Furious Five and must rescue Shifu and stop the foot clan. Splinter goes to help as well as April and Casey Jones. At the Foot Clan headquarters, Shifu is chained to the wall and sings on how sorry he is for himself for letting Tai Lung become a monster (Yesterday by Roy Clark).The turles and the Furous Five all prepare, with Leo and Donnie discussing strategy, constructing new equipment, and Raphael loading himself down with weapons. They all board the Shell Raiser to begin their mission.
The fight begins in the foots headquarters however, an enraged Shredder and his minions chase them down the city streets and into the subway in his car intending to snatch Sora from them. Dogpound and Fishface are both thrown onto the tracks in their fight with Sora, Splinter and Donnie, and presumably killed. Sora is thrown onto the hood of Shredder's van and Shifu tries to snatch her back while the wariors (mostly Mikey) drive. The warroirs manages to save Shifu while Sora, Splinter and Donnie fight off Tai Lung and Shredder. They emerge onto the Brooklyn Bridge, where Shredder's van collides with a train and he and Tai Lung are killed. Mikey manages to steer the Shell-Raiser onto one of the bridge's cables and they emerge unscathed. After the incident, Splinter, who along with Donnie and Sora were thrown away by Shredder and Tai Lung before his untimely demise, hands the cub a "thought to be dead" Donatello. Everyone else thinks he's dead until Jenny hears a soft voice talking to her, meaning that Donnie is alive. Everyone is rejoiced and accepted as Sora's new best friends, except Viper who is still in great shock from the chase.
The next morning,everyone sits down to a victory breakfast at the defeat of the two enemys.That same day the portal is begining to open so that ment the Jade Palace Warriors could go back to the Valley of Peace.Everyone says their goodbyes as Leo and his gang finally drive into the streets to make a new start (Why Should We Worry from Oliver and Company).Durring the credits we see the blooper for the film (Raining Sunshine from Cloudy with a Chance of Meatballs) After that everyone in the studio sings marking the end of the film (Somebody’s Got Your Back from Aladdin:A Musical Fantasy).