Season 12 brings spiraling drama and suspense to the lives of ER veterans. Abby and Kovac share unexpected news. Gallant comes home from Iraq to be with Neela. Pratt goes to Darfur to work with Carter.

Continues to chronicle life and death in Chicago's Country General hospital emergency room. Portrays the plight of medical students in their quest to become physicians. Healing is teamwork and science with instant decisions and best guesses to be made. Joy one moment, tragedy the next, but always a 24/7 readiness.

In 1952, twenty-three year old medical student Ernesto Guevara de la Serna (later better known as Ernesto Che Guevara) just one semester away from graduation, decides to postpone his last semester to accompany his twenty-nine year old biochemist friend Alberto Granado on his four month, 8,000 km long dream motorcycle trip throughout South America starting from their home in Buenos Aires. Their quest is to see things they've only read about in books...