In search of a mystical ingredient known as Sky Fish, Meliodas and Hawk stumble upon a spring that suddenly transports them to the Sky Temple: a breathtaking land above the clouds, inhabited by beings called Celestials. Meliodas, however, looks strikingly similar to a local criminal called Solaad, and is imprisoned and shunned as a result. Meanwhile, the kingdom of the Sky Temple prepares to defend the Great Oshiros seal—said to harbour a three thousand-year-old evil—from the malevolent Six Knights of Black, a group of demons who seek to destroy the seal. However, the Demon Clan is successfully unleashed and terrorizes the land, prompting the remaining Seven Deadly Sins and the Celestials to fight against their wicked foes.