Josh quickly moves up the corporate ladder, and enjoying the pleasures of adulthood, is tempted to leave behind his true identity. As Josh's excellence in his "career" casts him deeper into the life of a vice-president of development. He starts to make a greater impact on the MacMillan company, and Paul gets progressively more jealous of him and undergoes a sort of degenerative metamorphosis of his own. Josh becomes more adultlike and Paul more childlike. Susan, bored by anything childish, begins to lose interest in Paul, seeing Josh as a breath of fresh air. She approaches him at an office banquet, and is invited over to his apartment for a routine sleepover. Josh gets her to unwind, and they spend the night enjoying pinball machines and trampolines. For the first time in years, Susan feels like a child. They sleep in bunk beds and he gives her a compass ring. Armed with nothing but the shy awkwardness of a 13-year-old, Josh lays the groundwork for his first romantic relationship. Exhilirated by this forgotten feeling of young love, she slowly starts falling for Josh.
As adulthood begins to replace childhood, Josh's romantic love replaces the companionship of his best friend. Though Josh does go out to eat with Billy on his birthday, he leaves hurriedly and takes Susan to a carnival rather than spend the night with Billy. They kiss while dancing, and that night Josh loses his virginity to Susan. This is the point at which the second metamorphosis peaks. Josh begins acting like an adult and even begins wearing a suit to work. Billy finds Zoltar and meets with Josh to give him the great news to find that he has completely sold out. Josh is forced to choose between his two lives. He has "a million reasons to go home and only one reason (Susan) to stay." He tries to tell her the truth but she has to see his final metamorphosis to believe it. Her happiest times in the movie were those when she was with Josh, and in touch with her inner child, yet she declines the unreal opportunity to re-live her youth with Josh.