What's the last name of the person whose wife is running her first marathon?
In the beginning of the film, a brief overview of the history of the marathon is shown, with footage of dramatic races involving Dorando Pietri, Abebe Bikila and Rod Dixon.  Notable marathoners such as Frank Shorter, Dick Beardsley, Alberto Salazar, Grete Waitz, Paula Radcliffe, Joan Benoit-Samuelson, and Kathrine Switzer provide commentary about the sport.
The focus is then on the six featured runners and their training for the 2005 Chicago Marathon. American Deena Kastor and Kenyan Daniel Njenga are both elite runners, and are  determined to win the race.  Kastor was the bronze medalist at the 2004 Olympic Marathon, but has yet to win a marathon.  Njenga had finished second multiple times in previous Chicago Marathons.  Kastor is shown training and recovering from an injury in Mammoth Lakes, California, while Njenga's life as a sponsored runner in Tokyo is profiled.
The rest of the runners featured live in Chicago. Ryan Bradley and Lori O'Connor are both married young professionals; Bradley is a veteran marathoner who hopes to earn a qualifying time for the Boston Marathon, and O'Connor is running her first marathon.  She finds it humorous when colleagues ask if she expects to win.  Jerry Meyers is a jovial 70-year-old who claims to run marathons for the T-shirt.  Leah Caille is a new runner that took up the sport to help recover from an emotional divorce.
While preparing for the race, Bradley suffers a knee injury and is unable to compete. He is clearly upset by this, and takes out his frustration by going for a long bike ride. O'Connor and Caille go through the new experience of the long training sessions necessary for a marathoner.  Meyers lends his veteran knowledge while leading slower training runs with his daughter, who is running her first marathon.
Bradley