Believing her marriage to Andy to be perfect in every way, Ellen runs into former flame Leo and wonders why she has been unable to forget him even though they brought out the worst in each other.
After a night of indiscriminate partying, Rachel sleeps with a close friend's fiance and is consumed with guilt, until the intensity of her feelings forces her to make a difficult choice.
Meeting by chance when a fateful accident sends a six-year-old boy to an upscale Boston hospital, the child's mother and the doctor's stay-at-home wife find their lives changing in unexpected ways.