Molly Snow has always lived in the shadow of her older sister, Robin, who is a determined runner bound for Olympic greatness. Whereas Robin has always shone in the spotlight and is the apple of their mother's eye, Molly likes to remain behind the scenes, fulfilling her passion for botany, where she works in her family's business, the Snow Hill Greenhouse. Sometimes to her chagrin, Molly is also expected to support Robin's running, timing her practices and driving her to meets.

On a day Molly was supposed to be with Robin, tragedy strikes when Robin is found unconscious on the roadside by another runner. After being admitted to the ICU, it is determined that Robin had a massive heart attack that deprived her for oxygen for too long and left her brain dead. In the days that follow, each family is grappling with Robin's accident in different ways: Charlie, her father, tries to be the silent supporter, Chris, her brother, wants Robin off the life support, Kathyrn, her mother, believes that Robin will come out of this, and Molly just wants to do what Robin would have wanted, even though she doesn't know what this is.

While dealing with the guilt she feels for not being there for her sister, Molly is determined to do right by Robin and figure out what she wanted. Little does she know the family secrets she will unveil while looking for an answer.