Mark must overcome numerous obstacles, mostly weather-related, in order to get to the church to marry Elizabeth, who is stuck with both of her bickering, divorced parents. Abby has a major cold, but cannot leave the hospital, due to most of the nurses being at the wedding. Many patients come in to the ER from an accident involving a prison van; Luka and Carter clash over the treatment of an injured cop and a prisoner with a dislocated shoulder. While waiting for a flight to Vegas, Weaver (who wasn't invited to the wedding), strikes up a conversation with a friendly man. Chen misses her son. Cleo doesn't want to go to the wedding, because the bride is Peter's ex-girlfriend.

Abby goes to court to argue for a 90-day psych hold for her mother. Her mother is released, and later shows up at Abby's apartment, where Luka is cooking a romantic dinner for himself and Abby. Weaver treats an old children's television show host and an animal suit fetishist. Carla checks into the hospital after a fall. Benton treats Carl Ferris again after he suffers a heart attack. Malucci clashes with Jing-Mei and Cleo when his past track record gets him in trouble. Carter treats a young girl whose boyfriend has been interfering with her pregnancy by feeding her herbal root extracts to cause a natural abortion. Chen treats a patient with a talent for numbers. Malucci calls in a priest to perform an exorcism.