The following version of the book was used to create this study guide: Soontornvat, Christina. A Wish in the Dark. Candlewick Press, Somerville, MA, 2020. Kindle AZW file.

Pong and Somkit are young, orphaned boys who live at the Namwon Women's Reform Center, though everyone knows it is really a prison. Any child born at the center remains until his mother's sentence is fulfilled or the child is 13 years-old. Pong and Somkit are several years away from release. Pong often stares across the river at Chattana City. A large part of that city was destroyed by fire years earlier. The ruler there now is the Governor, who has the magical ability to create light which he traps in orbs. Fire is outlawed, and everyone uses orbs for light, cooking, and powering motors. Pong dreams of working for the governor someday.

Nok is the daughter of Warden Sivapan who oversees the prison. One day, Nok, along with her three siblings and mother, join their father at Namwon to welcome the Governor for a visit. Pong gets into a fight defending Somkit during the event. Nok is appalled that he would act that way in front of the Governor. The Governor has a quiet talk with Pong and hands him a glowing orb. That orb seems to symbolize hope for Pong, but the Governor snuffs out the light. Pong realizes there is no hope for a child born and raised in prison. A few days later, Pong takes the opportunity to hide in a trash basket. He is carried away down the river by the trash man. He has a moment of panic over leaving Somkit but is soon dumped along with all the garbage. Pong feels his only hope is to travel south, far from Chattana, where the tattoo identifying him as a prisoner will not matter. On the way, he passes through the small village of Tanaburi. Hunger drives him to steal some meat from the monks of Wat Singh. Mrs. Viboon catches him, but a monk named Father Cham speaks up for Pong. The unexpected kindness prompts him to remain with the monks for four years. During that time, Pong sees Father Cham hand out many blessings that seem frivolous.

Meanwhile, Nok's father has become a Commissioner who is supposed to enforce the Governor's laws. He arrives in Tanaburi because the villagers still use fire and do not buy orbs. Nok knows there is some secret her parents are keeping, and her mother alludes to the gossip that is endangering the family's social status. (She eventually learns that her father had an affair and Nok was born at Namwon.) When Nok sees Pong, she believes capturing him will redeem her family. Pong escapes. Everyone assumes he drowned, but he makes it back up the river to Chattana. Nok believes Pong is alive and follows him.

Pong still wants to escape, but he is soon caught up in the struggles of the poor and oppressed of Chattana. The poor band together and plan a demonstration against the Governor, but Pong takes an opportunity to leave before that march takes place. When he is near Tanaburi, he sees a vision of Father Cham and learns that the Governor's magic ability to produce light was one of Father Cham's blessings. It was given with good intentions but went horribly wrong as the Governor became too powerful. Pong realizes that true freedom lies not in running away, but in joining his friends as they fight for justice. He returns to Chattana. Nok has always accepted the Governor's proverbs as fact, but she begins to see the poor side of town and realizes the effect of the Governor's propaganda. She joins the marchers as the group faces the Governor. Pong joins them as well. Pong sees the bracelet that Father Cham gives each person he blesses, and he grabs the Governor's arm. Light flows from the Governor into Pong. Somkit and Nok touch Pong, and the light continues to flow until everyone on the bridge is glowing. The Governor's power is completely dissipated by the act. He leaves town. A short time later, things have changed dramatically in the province. Namwon is now a school. Nok is attending a prestigious girls' school, despite the scandal surrounding her birth.