Seventeen-year-old Marco Polo leaves his home in Venice on a trip to the little-known country of "Yuan", in the company of his father Nicolo and his uncle Matteo. Their mission is to deliver the sacred oil from the Tomb of Christ and a letter from the Pope to the Kublai.

The third season of One Punch Man. Saitama is a hero who only became a hero for fun. After three years of "special training," he’s become so strong that he's practically invincible. In fact, he's too strong—even his mightiest opponents are taken out with a single punch. Alongside Genos, his faithful disciple, Saitama performs his official hero duties as a member of the Hero Association. One day, monsters claiming to be from the Monster Association suddenly appeared, taking a child of Hero Association executive hostage. The S-class heroes gather and plan a raid on the Monster Association hideout to rescue the hostage. Meanwhile, Garou, a "human monster" who was taken by the Monster Association during a battle with the heroes, awakens in the Monster Association hideout.

The inhabitants of a certain wealthy town think nothing of throwing objects away. However, their waste is priceless to Rudo, a resident of the town's slums. Despite the constant warnings from his adoptive father Regto, Rudo spends his days searching for reusable materials that would otherwise be sent to the giant disposal area known as the Pit. Due to its vastness, the Pit doubles as a means of criminal punishment; those dropped in are never to return again. When Regto is murdered by a mysterious assailant, Rudo is falsely accused of the crime and thrown into the Pit. To his surprise, he awakens in a trash-filled area inhabited by enormous monsters formed from the junk. As the toxic air and Trash Beasts push Rudo to the brink of death, he is saved by Enjin, one of the Cleaners who wield weapons known as Vital Instruments to fight the monstrosities. Having gained his own Vital Instrument, Rudo soon joins the Cleaners in the hopes of finding a way to escape the Pit and avenge his father.

Despite being one of Zebrudia's few level 8 treasure hunters and the leader of the capital's top party, Grieving Souls, Krai Andrey does not deserve his prominent reputation. Everything he says somehow turns prophetic, which convinces everyone around him that he possesses unfathomable wisdom regardless of his utter incompetence. Krai knows his success is only a series of coincidences, but the weight of those expectations grows heavier as time goes by. Unfortunately, as the other members of the Grieving Souls continue to shock the world with their achievements, Krai's wish for a peaceful retirement drifts ever further out of reach.