Iris has never met her younger sister Zoey, but when Zoey transfers to her school and moves in for the semester, Iris is determined to be a model older sibling. Zoey makes that difficult: tall, confrontational, quick to skip class and dismiss authority, she has no interest in Iris's attempts to bond. Things grow more complicated when an unexpected and unwanted romantic tension develops between them—complicating everything Iris thought she understood about the situation and about herself.