One Wrong Step

Written by Jennifer A. Nielsen and originally published in 2025, One Wrong Step is a middle grade historical fiction novel that takes place in the 1930s during the beginning of World War II. In addition to its backdrop of the early days of mountaineering, the story features two young heroes, Atlas and Maddie, who risk their lives to save their fathers and the other members of a missing expedition on Mount Everest. The depiction of this ordeal allows Nielsen to explore themes such as Learning to Move Forward After Loss and Overcoming Challenges as a Team, and the protagonists also find themselves Navigating the Road to Maturity.

This guide refers to the 2025 Scholastic edition.

Content Warning: The source material and guide feature depictions of illness, death, racism, and religious discrimination.

Plot Summary

When Atlas was 12 years old, he summitted a mountain for the first time, scaling Kings Peak with his father in Utah. (The family had moved to Utah from England for the sake of Atlas’s mother, whose health was deteriorating.) However, when Atlas returned home from the trip, his grandfather told him that his mother had died. To this day, Atlas still hasn’t forgiven his father for taking him away from home when his mother was so ill. Atlas is now 14 and is preparing to climb Mount Everest with his father. The two do everything together, but they have a complicated and sometimes rocky relationship, given that neither father nor son wants to discuss the death of Atlas’s mother.

In the narrative present, Atlas and his father arrive at the Rongbuk Monastery in Tibet in August of 1939, one month before World War II breaks out. They meet their main guide, Chodak Sherpa, and the other members of the mountaineering expedition: Mr. Thomley (the expedition leader), Mr. Blake, and Mr. Levinsky. Atlas hopes to reach the summit with his father, but his father plans to leave him at Advanced Base Camp, where the conditions are still relatively safe. On August 14, Atlas and his father search for a water source, and Atlas is nearly crushed by a falling serac (ice formation). He freezes in fear as it falls toward him, and his father has to pull him out of the way.

The next day, Atlas’s team moves to Advanced Base Camp, where Atlas and his father encounter Mr. Pierson and his daughter, Maddie. (Atlas knows Mr. Pierson from a previous expedition in Austria; on that trip, Atlas became overconfident, went ahead of the group, and got lost. He nearly walked off a concealed cliff and froze in that moment too; Mr. Pierson was the one who found him.)

The group ventures out to practice climbing, and Mr. Blake accidentally steps on Chodak’s hand, injuring him. Atlas keeps asking to go to the summit, but his father adamantly refuses. When the group leaves for the summit on August 21, Atlas, Maddie, and Chodak stay behind, and Atlas is tasked with managing the radio calls. He receives a warning from Mrs. Thomley that Britain is calling all its men home due to imminent war, as well as another warning that a storm and high snowfall are likely. When Atlas passes these messages on, his father and the rest of the team ignore the warnings and continue their ascent.

When an avalanche strikes the area where the team is likely to be climbing, Atlas tries to reach them on the radio and gets nothing but static. He and Maddie are both eager to find and save their fathers, and they eventually convince Chodak to let them do so. At first, Chodak agrees only to climb to the top of North Col and test the radio again. One part of this climb involves a ladder across a deep crevasse. Atlas bravely volunteers to cross first and then coaches Maddie along. On the final portion of the climb, Atlas helps Chodak and Maddie reach the top. The radio still doesn’t work, but in the morning, Morse code starts to come through. It reads, “SOS,” and Chodak is finally convinced that a rescue mission is in order.

As Atlas and the others pack vital supplies, Atlas comes across a shovel that appears to have a Nazi swastika on it. Underneath the shovel is Mr. Blake’s notebook. Suddenly, Atlas is reminded of Mr. Blake’s interactions with a man named Mr. Schäfer, who worked for the Nazis and hoped to gain access to Mount Everest. Atlas begins to suspect that Mr. Blake is also working for the Nazis. Atlas, Chodak, and Maddie begin to climb the North Ridge. Maddie slips at one point, almost pulling everyone off the edge with her. Chodak begins to worry that he is more of a burden than an asset because of his hand injury. He allows Maddie and Atlas to go on alone and returns to Camp Four, where he plans to call for more help.

Atlas and Maddie climb the North Ridge, boosting each other over massive boulders. After a few dangerous moments, they finally reach Camp Five and take time to eat and rest; the words “Help” and “Blake” come through on the radio. When Atlas and Maddie contact Chodak, he tells them that help is on the way. The higher that Maddie and Atlas climb, the more intense their altitude sickness becomes. Atlas gets a horrible headache and a cough and then begins to hallucinate. Maddie becomes dizzy and weak. Still, they fight through their symptoms and continue to climb.

When Atlas and Maddie cross a ladder that stretches over a gully, Atlas slips off the cliff on the other side. He hangs over the endless gully as Maddie uses her ice axe to keep them both in place. As Atlas hangs there, he reflects on his grandfather’s advice to move on from his grief over his mother and start moving forward again. He realizes that mountaineering never actually helped him escape his grief, and he tells Maddie to cut the rope. She refuses. Instead, she manages to pull herself up and uses a fishing rod to pull Atlas up after her. Moments later, Mr. Blake passes by on his way back down the mountain and admits that he believes the others can no longer be saved. Atlas accuses him of being a Nazi sympathizer, and Mr. Blake takes offense before heading down the mountain.

Camp Six is cleaned out, likely by Mr. Blake. Maddie asks Atlas why he is always so angry. Atlas admits to his belief that his father betrayed him by not telling him that his mother was about to die. However, Maddie theorizes that his father was trying to do him a favor.

When Atlas drops his rucksack, his mother’s scarf goes with it, and he has no choice but to choose between the scarf and the last oxygen tank. Atlas chooses the oxygen tank but ends up losing both. It occurs to him that he has felt frozen since his mother died and that he must make the choice to move forward in life. Moments later, a Sherpa named Sonam approaches and helps Maddie and Atlas find the missing team members, who have become trapped under deep snow. Sonam, Maddie, and Atlas dig together until they open a space big enough to lower a rope and pull the group out, but Atlas passes out from exhaustion before he gets to see his father.

Atlas is carried down the mountain and later learns that everyone except one Sherpa survived the ordeal. His father remains unconscious for a while but eventually recovers. Mr. Thomley has broken his leg; five years later, he dies on his next expedition. Mr. Levinsky stays in Tibet, and Maddie goes back to Texas with her father. Atlas goes back to London with his father, where he works to transport injured soldiers from trains to ambulances when they arrive home. One day, a woman whose son was injured in the war approaches Atlas and shows her gratitude by giving him her scarf. Atlas sees this gesture as a sign of peace from his mother, and he maintains his hope that the war will one day end.