The protagonist, known as "Zakku Baran" or "Kinsetsu Oyaji" (Close-Combat Old Man) by his gaming peers, spends his evenings at an arcade playing "Guardian Troopers," a complex robot action game. Despite his self-deprecating nickname, he is a skilled player, particularly adept at close-quarters combat. His primary motivation is to earn enough in-game score points to play for free and potentially profit from selling in-game items on auction sites.
The narrative follows Zakku's progression through the game's challenges. He starts by practicing in CPU-controlled stages, mastering his preferred robot, "Lynx," and its Buster Sword. He faces increasingly difficult CPU opponents, including spider-like mechs, crab-like mechs with pincers, and a formidable multi-legged battleship. A significant turning point occurs when he discovers that in-game items can be sold for real money through online auctions, providing a potential escape from his low-paying, overtime-heavy job. This discovery fuels his determination to excel in the game.
Zakku also engages in player-versus-player battles. He encounters various opponents, including those using the popular "Scutum" robot, known for its powerful beam gun and shield. He initially struggles against skilled players but gradually improves his tactics, incorporating new weapons like the "X Caliber" sword and the "Wire Anchor" for enhanced maneuverability. His close-combat specialization is challenged by enemies with superior firepower and varied attack patterns.
World-building elements include the game's intricate control system, the rarity of certain mechs and weapons, the existence of a "Guaranty System" that rewards players for publicly sharing their match footage, and a special "Casino Special Zone" where score points can be exchanged for real currency. The game's mechanics are detailed, including weapon durability, repair systems, and the impact of environmental factors like gravity and water resistance on gameplay.
Emotional beats are driven by Zakku's frustration with his mundane work life, his growing excitement and passion for the game, and his determination to overcome challenges. He experiences moments of triumph, such as clearing difficult stages and winning player matches, but also faces setbacks and the realization of his limitations. The story also touches upon the exploitative nature of his workplace and his growing desire for financial independence.
As Zakku progresses, he faces tougher opponents and learns to adapt his strategies. He acquires new weapons and equipment, including the "Sword Breaker" and the "Plasma Launcher," and experiments with different combat styles. The narrative culminates with Zakku facing increasingly difficult challenges in the game's tournament mode and contemplating his future, both in the game and in his real life, as the potential for significant financial gain through "Guardian Troopers" becomes more apparent. He also grapples with the game's mechanics, particularly in challenging underwater and blizzard stages, and the social dynamics of the arcade community.
