Masato Ōsuki, a teenage boy, enters a government-sponsored MMORPG with his mother Mamako to strengthen their bond. Transported into the game world, he anticipates power fantasies but grows frustrated as Mamako consistently outperforms him through superior stats and overpowered abilities.

He exhibits typical teenage embarrassment toward Mamako's affectionate behavior and attempts to reconnect with their past closeness, a dynamic intensified by her youthful appearance that could pass for a high schooler. Despite frequent irritation and open threats to disown her during extreme conflicts, underlying care for his mother remains.

Adventures with party members Wise, Porta, and Medhi drive his development. Witnessing their strained maternal relationships—Wise's abandonment, Medhi's overbearing mother, and Porta's unspecified family background—grants Masato insight into parenting challenges. This gradually fosters appreciation for Mamako's efforts, marked by reconciliations after heated arguments and acknowledgments of her combat support.

An OVA beach incident triggers retrograde amnesia, causing Masato to forget his party and recognize Mamako solely as someone "important." Freed from habitual embarrassment, he displays uncharacteristic affection, nearly confessing romantic feelings and attempting a kiss before a kraken attack restores his memories. Later light novel volumes introduce his father, Hayato, who joins the game disguised as "Hawk" to evaluate the family for a final challenge. Masato remains unaware of Hawk's identity, while Mamako instantly recognizes her husband.

In combat, Masato specializes in single-target aerial attacks wielding Filamento of the Vast Horizon—a sword compensating for Mamako's ground-focused limitations. His Magic Reduction Armor grants partial debuff resistance, establishing them as a complementary team where Mamako handles ground enemies and Masato manages airborne threats.