A frantic Sam and Luka report diabetic 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, Sam tell... (more)s Luka she doesn't want anymore kids. After finding Alex safe, Sam tells him the truth and takes him to see his father. In the ER, Susan, Pratt, and the nurses evaluate Ray, Neela, and Abby’s first days as R2s, while each of them struggle to manage patients, new interns, and their first attempts at teaching.