Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Wistful, Childishly Naïve
Wistful
This book is so into looking backward with longing, that even Apa—who seems kind of unredeemable toward the end of the book—gets a sepia-toned treatment from Young Ju's narration.
For example, we find out that the nameless adult who patiently and sweetly teaches Young Ju how to brave the ocean's waves in the first chapter, turns out to be her dad. Here's Uhmma, reminding Young Ju of how great Apa could be:
He loved the waves, Uhmma says. I remember how worried I was to see you go into the water. But somehow he taught you to be brave that day. You loved the waves after that. Never wanted to come out… What dreamers you two were! Pretending to be dolphins, then seals, then ships that could sail far across the sea. Uhmma suddenly turns away from me, looks out the window of our new home. After a moment she says quietly, He was a different man back then. (30.47-49)
What's Young Ju's response to her mom's trip down memory lane? She:
trace[s] the faces in the picture with [her] fingertips. [She] can barely remember the feel of [Apa's] arms as he held [her] tight and asked [her] to be brave. How scared [she] was of the waves, of what might be out there. (30.50)
See what we mean? Her Apa might have high-tailed it back to Korea (without even saying good-bye to them, mind you), but that doesn't mean that the memory of a good Apa or the wish that he could have been a different man in America can't be resuscitated. All of which just means that, in this story, there aren't true bad guys—just characters who could have been different.
Childishly Naïve
What do you get when you put a kid in charge of telling a story?
Sentences like this: "I am a sea bubble floating, floating in a dream. Bhop" (1.18). It's the kind of writing that completely doesn't make sense unless you're (day)dreaming without limits—you know, the way kids do. Why can't we be sea bubbles floating in a dream? If your answer is "Because it's not real," then you can say with confidence that you're not childishly naive.
But all this naïveté is important; it lets us sympathize with Young Ju. It's a reminder of how young—and therefore fragile—she is, so when her father does something like slap Uhmma, his actions aren't just a little brutal—they're really brutal: "I do not see Apa's hand. It is too fast. I only hear the slap, loud as breaking glass" (9.22).
See what we mean? Violence shatters Young Ju's naïve voice and worldview as if it's "breaking glass," but Young Ju's simple observations also maintain her naïveté and make her appear that much more a victim of Apa's brutality.