Super Shiro is the secret superhero identity of Shiro, the Nohara family's ordinary-looking white dog. As Shiro, he lives as a frequently overlooked family pet, particularly by Shin-chan, yet displays significant intelligence and responsibility. He independently walks himself, forages for food when meals are missed, and diligently cares for the infant Himawari, even sacrificing his own safety for hers. Shiro cleverly adapts, like pretending to be a stuffed animal to join his family in pet-restricted areas.

When alone or when Earth is endangered, Shiro transforms into Super Shiro by donning a special superhero badge. In this form, his thoughts gain a distinct, deeper internal monologue voice, contrasting his usual dog sounds. His core mission is locating the legendary "Bobobobobone," a bone-shaped artifact rumored to grant world-ruling power, identifiable solely by its "glorious, elegant, and wild" scent. Super Shiro teleports potential bones to his alien ally Bibo for verification; incorrect choices cause explosions, resetting his quest.

Super Shiro regularly battles antagonists like Dekapoo, a scheming canine scientist seeking the bone for world domination, and Can Can, a privileged dog pursuing it for social status. Their conflicts involve repetitive, evolving comedic sabotage during searches. Despite their rivalry, interactions reveal unexpected depth, including moments where Super Shiro rescues Dekapoo from danger or receives aid in return, hinting at complex dynamics.

His personality blends diligence and restraint; he avoids unnecessary heroics unless duty calls. He maintains his ordinary pet life, keeping his dual identity hidden from the Nohara family. His experiences include diversions from the bone quest that showcase adaptability, such as aiding ant colonies or navigating everyday obstacles like cold weather and construction sites.