Turtles in the Turtle Sub

While the turtles were about to go to the underwater to destroy the kraang,all four brothers figured that they need to stop the kraang of polluting the water.While they destroyed it and went to the giant turtle submarine,it got broken by the sea monster what the kraang brought.The turtles were fast and went to the surface,but Leo was still behind,and run out of air,but he heard a singing that was so beautiful that he never heard,who,or what saved him?Find out in the story.I hope you all like it?