Teacher Poppy Cross (Sally Hawkins) is an eternal optimist who lives with her more cynical friend Zoe (Alexis Zegerman). Deciding she wants to learn to drive, she starts taking lessons from Scott (Eddie Marsan), a tense and downbeat instructor who believes Poppy's levity reflects a lack of seriousness. Although they clash, Poppy is not deterred from her goal. Meanwhile, she starts dating Tim, a social worker who came to her school to help a child.