Fireflies is the coming of age story of a fifteen-year-old girl who struggles to rescue her grandfather from a nursing home.
Taylor (Kate Mara), the film's heroine, desperately wants to learn to drive. Jack (Dan Frazer), Taylor's grandfather, is the only person who will teach her. When the two of them steal the family car and go out on a late-night expedition, they nearly get into an accident. This gives Tony (Brian Delate), Taylor's step-father, and Grace (Isabel Glasser), Taylor's mother, the excuse they have been looking for to put an end to Taylor and Jack's friendship.
Tony and Grace take Jack to the Golden Age Residence - home to a host of lost characters. For the first time in her life, Taylor is faced with the possibility of losing the one person in the world she truly cares about. She collects her savings and escapes with Tony's car. Still a novice driver, she braves the dark roads of suburban New Jersey in an attempt to break Jack out of the Residence before it is too late.