Sam and Luka report Alex missing after he runs away to find his father. Acting on information from the police, they follow a lead to Iowa, then eventually head for Colorado. As they travel, they discuss their relationship, slowly realizing they have very little in common. With Alex safe, Sam tells him the truth about his father and takes him to see him. In the ER, Susan, Pratt, and the nurses evaluate Ray, Neela, and Abby's first days as R2s, while each of them struggles to manage patients, new interns, and their first attempts at teaching.