Kuppa, an 11-year-old boy and central protagonist, thrives on adventure as a treasure hunter in a desert-dominated future world where water scarcity makes it the planet's most valuable resource. He traverses the harsh environment wielding a large sword on his back, accompanied primarily by his robot assistant, Dram. Dram relies exclusively on water as its energy source, imposing a recurring financial burden due to water's high cost, and possesses three transformation modes: "Barrel Mode," "Battle Mode," and "Hyper Mode."

Kuppa exhibits a bold, often reckless approach when confronting dangers, including villains and desert hazards. Despite this impulsiveness, he consistently shows compassion toward vulnerable individuals and actively opposes injustice. His 14-year-old sister, Yukke, significantly influences him; she frequently criticizes his actions and worries about his safety. Kuppa openly acknowledges her authority and shows apprehension toward her reprimands.

His treasure hunting involves seeking valuable artifacts and advanced technology buried in desert ruins. This occupation places him in direct conflict with Bibmba, the leader of the criminal organization Pulcogi, which monopolizes water distribution. Bibmba pursues Kuppa as part of his self-described hobby of "hunting treasure hunters." Another figure is Samgetan, a mysterious individual possessing the precious stone "Aqua Luna" and purportedly observing humanity for millennia. Samgetan attracts Yukke's romantic interest, though his true intentions remain ambiguous.

Kuppa collaborates with Yukke in treasure hunting, maintaining a competitive dynamic. Yukke operates her own robot assistant, Jet, whose refined demeanor contrasts with Dram’s functionality. Together, the siblings navigate threats from Bibmba’s operations and the inherent perils of the desert landscape, including dangerous creatures guarding scarce water sources.