Will accompanies Maggie to her family reunion on their day off. As she's leaving for the airport, Maggie's sister loses her vision and crashes her car. They take her back to the ED to find out what's going on. As soon as her symptoms are treated, she tries to leave. Maggie convinces her to stay for some testing. The results indicate that she may be battling cancer -- but they can't be sure where. Will does a preliminary exam with an ultrasound, and is shocked to find that Denise has an enlarged prostrate. He reprimands Maggie for not pushing her sister to reveal that part of her medical history. Old wounds are opened up when Maggie wants Denise to stay for treatment but Denise insists on going back to Dallas. Eventually, Maggie convinces her to stay, and the two will work on their relationship while Denise heals.
Connor treats a VIP patient who strokes out after a polo injury. He uses Latham's religious observances as an excuse to circumvent his authority and oversight. Sharon has him call in Latham to help with the difficult procedure that he has already set in motion. Latham questions his ability to succeed under the time constraints, but Connor insists on going forward. He ends up having to have Latham step in to finish the surgery. He later endorses Latham as head of the department to Sharon, and attempts to make peace with the attending.
Ethan calls in Charles and Sarah after his patients ultrasound comes back with a disturbing result -- there is no baby. Charles and Sarah assess her, and as there is no sign of underlying psychosis, they diagnose her with a "hysterical" pregnancy. Sarah is tasked with breaking the news to the couple, and the woman doesn't react well. Sarah is racked with guilt, and unable to perform her duties (suggesting an extreme treatment), so Charles sends her home. After missing the shuttle to the parking garage, she runs into the (not) pregnant patient, and understands the situation more after speaking to her. Charles finds her at the hospital playground later, determinedly hitting the books.
Jeff is assigned to shadow Nat, leading to a little awkward flirtation throughout their day. Their patient doesn't speak English, but they can't find a translator for the specific Indonesian dialect he does speak. At first they are unable to determine what is making him ill, but after a consult with Will, Natalie goes back to basics and figures out that he recently visited an amusement park that was the site of a measles outbreak.
Will decides to go after Nina.