Arnold and Gerald must uncover an important document in order to save their neighborhood from a greedy developer. Sheck plans on destroying the neighborhood so that he can make a mega mall. With the future of their neighborhood at risk, Helga conspires against her father to help Arnold and Gerald. At the same time; Phil and the boarders, along with Big Bob (after realizing he will be swindled by Sheck) try to stop the construction crew from wrecking the neighborhood.—dawsonpersi