Lily and Zach's relationship begins with friendship. Lily says the first time they meet, "We're going to be friends" (117). For each of them, in their first encounter, there is a bit of guardedness, since Lily has never really known an African-American male of her own age, nor has Zach really known a white female of his age before this encounter. Southern people in that time and place were severely segregated. While August had told Lily enough about Zach for her to know he was African-American before they met, August had not mentioned anything to Zach about Lily being white, and he is shocked to discover this. Lily is shocked, because of her own prejudiced upbringing, to find Zach a very handsome young man. In addition to the physical attraction Lily feels, even though she is not really conscious of this, Zach has a sense of humor and knowledge of the world that she does not, for example, about music.
Their friendship deepens through their working together in the honey house, as they get to know what they have in common and how they are different. Both are missing a parent, Lily, her mother, and Zach, his father. Each of them has ambition well beyond the expectations of their upbringing. Zach wants to become a lawyer and Lily to become a writer. In many ways, Zach is far more sophisticated than Lily, having an interest in the politics of the day, for example. Lily has led a fairly sheltered life until this point.
In spite of the racial divide, as time goes on, Lily and Zach's physical attraction to one another increases greatly, and combined with the deepening friendship, what they feel is love. Lily says,
It seems like I as now thinking about Zach forty minutes out of every hour (133).
Zach is more guarded, saying,
Lily, I like you better than any girl I've ever known, but you have to understand, there are people who would kill boys like me for even looking at girls like you (135).
When Zach ends up in jail for having stood with his friends against a group of white racists in an encounter in town, Lily visits him and gains an insight into the underlying connection between them, saying,
I watched him, filled with tenderness and ache, wondering what it was that connected us. Was it the wounded places down inside people that sought each other out, that bred a kind of love between them? (184)
Zach's imprisonment leads to May's suicide, and this places a burden of guilt upon Zach, as well as a new anger at racial injustice. He becomes more politicized, while Lily would like to go back to the more "innocent" times before all of this happened. But finally, in a scene in Chapter 11, Zach and Lily have their first kiss, and Zach vows that he will change the world so that he and Lily can be together. He gives her his dog tags as a symbol of his pledge.
As the book ends, Zach is attending the white high school, and he and Lily remain together. What will happen in the future is not clear, but we hope that they can remain together always because in spite of all the superficial factors that suggest these two should not be together, they are a good match, both intelligent, goodhearted people who have experienced pain and loss that have made them understand and love one another. A more cynical person might say this was puppy love, but I like to picture them together still, with some children and some beehives.