Throughout Defy the Night, darkness, shadows, and the night itself symbolize secrecy and mystery. Because distribution of free medicine is illegal in Kandala, Tessa and Wes must use the cover of night to do their work. On the other hand, light and day symbolize honesty, doing things out in the open. Unlike most sectors of the kingdom, the Royal Sector has electricity and searchlights that can cut through darkness because they can afford them. These searchlights are meant to secure the safety of the royals and elites, but they’re also a danger to Tessa because they threaten to expose her illegal activities.

Early in the novel, Tessa and Wes both agree that it’s best to use the cover of night and masks to protect their identities. However, the changes they’re able to incite while hiding are limited. This is why Tessa argues that they should step into the light and do more (by sharing her dosage theory, etc.). At first, Corrick thinks this is too dangerous, but realizes that embracing the truth is necessary for lasting change. He, as himself, and Tessa eventually reveal their part in distributing free medicine, which allows both Harristan and the rebels to realize they were being deceived by another party altogether (the Benefactors).