Dr. Manning and fourth-year medical student Jeff Clarke are forced to figure out a mystery illness when an Indonesian man who doesn't speak English arrives at the hospital in dire straights. Maggie takes Dr. Halstead to her family reunion where he meets her sibling Denise and uncovers deep-rooted family secrets. Meanwhile, Dr. Rhodes takes on a complicated heart surgery without consulting Dr. Latham and Dr. Reese and Dr. Charles encounter a woman experiencing an unusual pregnancy.