Ushio to Tora centers on the struggles and battles of Ushio Aotsuki, who is persistently stalked and assisted by a colossal, supernatural, and occasionally invisible tiger-like creature. Ushio's family runs a Shinto temple in Japan, where, roughly 500 years ago, his samurai ancestor fought that very tiger to a stalemate, ultimately trapping it against a rock with a consecrated spear known as the "Beast Spear." Besides being a formidable weapon in its own right, this spear can grant its user the martial prowess of the ancestor who originally wielded it. Ushio inadvertently unsealed the cave where Tora was imprisoned. At first, Ushio declines to remove the spear holding Tora down, but Tora's release summons various monsters eager to fight him, and consequently Ushio. Ushio is compelled to free Tora, who desires to eat Ushio but refrains because Ushio keeps the spear nearby. The series highlights their dynamic, interspersed with clashes against mythological adversaries and Tora's efforts to navigate modern life.