A grandfather and grandson are injured in a chainsaw accident, leaving Luka stuck upstairs with one of them in a difficult case. Pratt has his trial-by-fire when he has to handle the ER alone, juggling multiple traumas, teaching duties and a troublesome intern. Neela mentors a new med student, and lends a hand when Pratt makes a serious error. Abby enrolls in a "Mommy and Me" class, but it's not all fun and games.