LitCharts assigns a color and icon to each theme in Holes, which you can use to track the themes throughout the work.
Fate and Destiny
Cruelty vs. Kindness
Justice
Power, Money, and Education
Man vs. Nature
Summary
Analysis
Stanley wonders if there are more onions around. He pulls up one of the white flowers, including the roots. The narration jumps back to the past; Sam is selling onions on the streets of Green Lake. Mrs. Tennyson, a very proper woman, runs after Sam in her nightgown. She stops him and explains that her daughters will be okay, thanks to Sam's onion tonic. She derisively says that Doc Hawthorn was useless, as he wanted to use leeches.
The juxtaposition of Stanley discovering onions with Mrs. Tennyson's insistence that onions cured her daughter reinforces that onions are life-saving within the world of the novel. Onions contain chemicals that help the gut remain healthy, which is likely how and why they're able to help Zero and Mrs. Tennyson's daughter.
Active
Themes
Hattie Parker and other townsfolk gather, and Hattie asks Mrs. Tennyson if her husband is aware of the way she's dressed. Mrs. Tennyson curtly explains that she and her husband have been up all night with their daughter, who ate bad meat—Hattie Parker's husband is the butcher. Hattie's face flushes. She excuses herself and Mrs. Tennyson buys onions from Sam. When she insists he keep the change, Sam asks her to buy onions for Mary Lou with it.
Hattie's derision falls right in line with her assertion that God would punish Katherine and Sam; her sense of right and wrong is focused entirely on manmade systems and moralities at the expense of the actual humans negatively impacted by that focus.
Active
Themes
Back in the present, Stanley and Zero take the next two days to recover. They eat onions and drink the dirty water. Since Zero seems to be feeling marginally better, Stanley decides to go look for the shovel. He feels strong as he heads down the mountain. After a while, he looks back and doesn't think he could've carried Zero so far, so he reasons he must've missed the shovel. Regardless, he keeps going just in case. Finally, Stanley sits down and decides that if he's so tired after walking down, he never would've been able to carry Zero up. However, Stanley finds the shovel and the sack of jars right next to each other.
Stanley's surprise at his own apparent strength suggests that he is, to some degree, unaware of the power of kindness and of caring about someone—his belief that Zero was worthy of care, coupled with the help from the natural world, is what enabled Stanley to carry Zero up the hill in the first place. This shows that even though the reader may make some of these connections, Stanley likely won't make all of them.