The show stars fourth grader Arnold, a boy who lives with his paternal grandparents, Phil and Gertrude, proprietors of the Sunset Arms boarding house. In each episode, Arnold often helps a schoolmate solve a personal problem, or encounters a predicament of his own. The show also focuses on Arnold's classmate, Helga, who often treats Arnold cruelly and bullies him constantly. However, a recurring theme of the show is the fact that Helga pretends to dislike Arnold to hide the fact that she is secretly in love with him.