The air conditioning quits on the hottest day in October which, coupled with closed ERs in Chicago's other two hospitals, leads to an extremely hectic day. Dr. Ross treats a six-year-old suffering from a cocaine overdose; Ivan Gregor, the liquor store owner, shoots and seriously wounds a young teenager. Susan's immature sister Chloe drops by, wreaking havoc in Susan's life. Doug picks up a pharmaceutical saleswoman, much to Carol's displeasure.

Hathaway treats a rape victim. Walt brings Benton's mother to the ER with a sprained ankle. Carter shows his annoyance toward Benton and his stand-offish attitude. Mark calls in sick to spend time with his wife, leaving Doug as a hectic acting chief. Div shows signs of snapping, overreacting at the smallest provocation. The ER gets a new desk clerk, 'Bob'.