Sam Houston hails from Ataraxia's Education World, forging an enduring childhood bond with Jomy Marcus Shin. Both undergo the mandatory adulthood examination at fourteen, a memory-wiping ritual enforced by the Superior Dominance. While Jomy fails due to latent Mu genetics and is rescued by the Mu resistance, Sam passes and transfers to elite training at Educational Station E-1077.

There, Sam develops a profound connection with Keith Anyan, a fellow student devoid of childhood or examination memories. Sam exhibits unwavering loyalty and kindness towards Keith, defending him against detractors and supporting him through critical incidents like a perilous rescue mission after a dock collision. This steadfast friendship establishes Sam as Keith's moral anchor within the station's rigid confines.

Sam's mental stability fractures under repeated psychic encounters with the Mu. These interactions trigger a regression to an eight-year-old mentality, erasing all memories since his examination and reviving only the suppressed childhood experiences the Superior Dominance intended to eliminate. Ironically, this state preserves his earliest memories of Jomy and Ataraxia.

His physical decline culminates in death from pneumonia after wandering for hours in the rain, lost in nostalgic recollections. Keith discovers his body and carries him back indoors. In a symbolic act, Keith preserves samples of Sam’s blood within his earrings, maintaining a tangible link to his friend.

The anime adaptation grants Sam expanded narrative presence compared to the original manga, emphasizing his relationships with characters like Swena Dalton—another childhood friend from Ataraxia—and his vital role as Keith's primary emotional support. His existence and tragic end underscore central themes of memory suppression and the emotional toll exacted by the Superior Dominance regime.