"Tiger Mask" centers on Naoto Date, a professional wrestler who adopts the persona of Tiger Mask, a character originally created as a villain in the wrestling world. The series begins with Naoto's return to Japan after achieving fame in the United States. His wrestling career is marked by his signature tiger mask, which symbolizes both his identity and his connection to a mysterious organization known as Tiger's Den. This shadowy group trains orphans to become ruthless wrestlers, exploiting them for profit and power. Naoto, once a member of Tiger's Den, has since turned against the organization, seeking to dismantle it and protect others from its influence.

The narrative explores Naoto's dual life as a wrestler and a vigilante. In the ring, he faces formidable opponents, many of whom are also products of Tiger's Den, while outside the ring, he works to expose the organization's corruption and rescue children trapped in its grip. His efforts are driven by a desire to atone for his past and to honor the memory of his mentor, who sacrificed himself to save Naoto. The series delves into themes of redemption, justice, and the struggle between good and evil, as Naoto battles both physical opponents and his own inner demons.

Key characters include Ruriko Takigawa, a journalist who becomes Naoto's ally and love interest, and Mister X, a recurring antagonist who represents the darker aspects of Tiger's Den. The series also features a range of wrestlers, each with unique personas and backstories, who challenge Naoto in the ring and contribute to the overarching conflict with Tiger's Den. The wrestling matches are central to the plot, serving as both physical confrontations and symbolic battles between Naoto's ideals and the corruption he fights against.

As the story progresses, Naoto's journey becomes increasingly intertwined with the lives of those around him, including the children he rescues from Tiger's Den. His actions inspire others to stand against the organization, leading to a climactic showdown that tests his resolve and his commitment to his cause. The series balances intense wrestling action with moments of emotional depth, creating a narrative that is both engaging and thought-provoking.