Rachel is in tears on the train home from ballet class. Her teacher has told her that if she can’t lose weight she will be out. And her dance partner and crush, Simon, has been paired with the young, flirty Linda. So when the young woman opposite her on the train offers Rachel a tissue and a listening ear, Rachel tells her everything. But, does Amy genuinely want to help Rachel, or does she have darker motives for befriending the school girl?