"The Seven Deadly Sins: Four Knights of the Apocalypse" is a sequel to the original "The Seven Deadly Sins" series, set in the same universe but focusing on a new generation of characters. The story centers on Percival, a young boy raised in isolation on the remote island of God's Finger by his grandfather, Varghese. Percival's life takes a dramatic turn when a mysterious knight named Ironside arrives, revealing that Varghese is actually the legendary Holy Knight Liones and that Percival is destined to become one of the Four Knights of the Apocalypse, prophesied to bring about the world's destruction. After a tragic confrontation, Percival sets out on a journey to uncover the truth about his lineage and his role in the prophecy.

Percival is joined by a diverse group of companions, each with their own motivations and connections to the unfolding events. Among them is Donny, a skilled archer with a mysterious past, and Nasiens, a healer with a deep knowledge of magic. As they travel, they encounter various factions, including the remnants of the Holy Knights and the forces of chaos led by Arthur Pendragon, who has become the King of Chaos. Arthur's transformation into a tyrannical ruler seeking to reshape the world adds a layer of complexity to the narrative, as his actions directly influence the rise of the Four Knights.

The plot explores themes of destiny, identity, and the consequences of power. Percival's journey is marked by battles, alliances, and revelations about the true nature of the prophecy. The Four Knights of the Apocalypse are not merely agents of destruction but are tied to a larger cosmic balance, with their emergence linked to the resurgence of ancient evils and the potential for renewal. The series delves into the moral ambiguities of its characters, as Percival and his allies grapple with their roles in a world teetering on the brink of chaos.

The narrative is driven by a mix of action, mystery, and character development, with a focus on the evolving relationships between Percival and his companions. The story also revisits elements from the original series, connecting the past and present through recurring characters and lore. As the Four Knights' identities are gradually revealed, the stakes escalate, leading to confrontations that test their resolve and challenge their understanding of the prophecy. The series maintains a balance between episodic adventures and an overarching plot, building toward a climactic resolution that ties together the fates of its central characters and the world they inhabit.