When Peter first encounters Lola, their differences are so stark it seems improbable that any common ground could ever be found between them. Spirited away from an orphanage and plunged into a bewildering maze, both blindfolded and bound, they find themselves thrust into a predicament without rhyme or reason. Once Peter is unshackled and his sight restored, he retreats into the sanctuary of a daydream, seeking refuge from the menacing labyrinth and his own paralyzing fears. Emerging from this reverie, he discovers Lola, with her gruff intonation and brash demeanor that initially leads him to mistake her for a boy. Though more assertive than Peter, she shares in his perplexity about their presence in the ominous House of Stairs. Unlike Peter, however, Lola is resolute in her refusal to succumb passively to their mysterious plight.

As the narrative unfolds, Blossom emerges, characterized by her corpulent frame, selfish nature, and a sense of entitlement. Her manipulative and spiteful attitude, particularly towards Lola, adds tension to the group dynamic. Meanwhile, Oliver exudes an easy charm and athletic prowess, desirous of leadership yet devoid of the moral fortitude such a position demands. He exploits Abigail's affection, feigning interest only to later withdraw into aloofness, a move which perversely deepens her infatuation. Abigail's weakness is compounded by her fear of rivalry within the group.

Through the trials faced by these five characters, Sleator delves into the profound impact of environment on human behavior and the diverse ways in which individuals respond to such influence. Although the scenario may appear fantastical, it echoes real-life experiments conducted on animals like pigeons, rats, and dogs, and reminds us that humans, too, have been unwitting participants in governmental or corporate experiments. By starkly illustrating how these characters' actions are manipulated, Sleator heightens awareness of subtler forms of behavioral control that permeate everyday life, mirroring the unsuspecting manipulation the characters endure.

In House of Stairs, the clash between virtuous and malevolent forces is vividly portrayed. The experimenter, who emerges as the embodiment of malice, represents the type of evil that obscures clarity and compels individuals to compromise their potential. Despite claims of acting under the guise of security, order, comfort, and efficiency, Sleator leaves no doubt that such justifications hold no moral ground. Only characters like Peter and Lola, who resist evil's allure at all costs, are truly virtuous.

The novel also explores the individual's quest for freedom amidst a society that demands conformity. By defying conformity, Lola and Peter risk their very lives, while others sacrifice their autonomy in a misguided quest for self-preservation. Ironically, it is Lola and Peter who remain vibrantly alive by the novel's conclusion, as others devolve into mere automatons. Other themes in House of Stairs include the potential for personal redemption through meaningful connections, the juxtaposition of weakness and strength, and the pervasive influence of peer pressure.