Nurse Jeanette Makins (JoBeth Williams) arrives ready for what she expects to be a normal day at Memorial Hermann Hospital, but Tropical Storm Allison's rains return, and a normal day quickly turns into a nightmare. The most devastating storm in the history of the United States, Tropical Storm Allison hit southeast Texas in June 2001. With over $5 Billion in damages, over 45,000 left homeless, 22 people dead and over 70,000 vehicles flooded, it hit with a catastrophic one-two punch. During its second pass through the area, Allison dumped nearly 40 inches of rain on Houston alone within a 14-hour period. Four hospitals were closed temporarily because of flooding and damage, making situations difficult for affected patients and healthcare providers.