Robo Fusion Failure (ロボ合体不能 Robo Gattai Funō) is the twenty-eighth episode of Kousoku Sentai Turboranger. This is the beginning of a three-episode arc involving a massive realignment of the Boma, featuring the final battle with Dark Boma Zimba and the first appearance of the Turboranger's new base and mecha, the Turbobuilder, the first Enormous Base Robo in Super Sentai. It also is notable for the first appearance of a mysterious girl who only appears in Yamimaru's dream at this point but who will become key towards the series after this arc.