An old army buddy and fellow surgeon visits Conrad at the hospital. Meanwhile, the team is put to the test when they have to save the life of an uninsured and undocumented patient, while simultaneously battling the hospital's administrators, who fear the patient will cost millions. Also, Dr. Bell experiments with a new medication for his tremor and Nic swears to investigate the mystery surrounding missing medical records.

As Conrad battles a group of overly aggressive attending physicians on behalf of a patient with a mysterious chronic ailment, he also must face off against his father who has shown up at the hospital unannounced. When Mina goes out of her way to help a young man from her neighborhood who almost mugged her, Nic offers her assistance and discovers a secret that Mina has been keeping behind closed doors. While away from the hospital, Nic enlists the help of Devon to keep an eye on Lily, which leads him to an incredible find that has him questioning Dr. Lane's motives. Also, Renata's plans to poach a renowned surgeon from another hospital hit a standstill when Bell decides he doesn't agree with him.

Conrad is hit by a bike and badly sprains his ankle, but works through it when he takes the case of his old medical professor, who is hallucinating visions of her old patients. Devon is tasked with admitting Conrad, who refuses any sort of treatment. Nic tries to navigate her emotions while mourning the loss of a patient and Bell operates on a foreign dignitary with unforeseen complications. Meanwhile, Lane and Bell's relationship grows closer.

Halloween at Chastain proves to be just as spooky as ever when Conrad is tasked with diagnosing a young woman admitted to the hospital with extreme night terrors. Meanwhile, Devon faces his first Halloween in the ER, Nic panics over her decision to bring her newly sober sister to Mina's epic annual Halloween party and Bell finds an interesting way to make use of his new assistant.