At night, the god Zeus summoned Poseidon, claiming that his son had stolen the lightning fire, and threatened him to go to war if he did not retrieve it as soon as possible. In reality, Poseidon and his wife Sally's son, Poseidon, is a college student. The 17-year-old can stay underwater for 7 minutes, but is not interested in the teacher's questions about Shakespeare. While visiting the museum, he meets Teacher Ma (Pierce Brosnan) in a wheelchair. However, the literature teacher transformed into a goddess of revenge and asked him for the whereabouts of lightning fire. Fortunately, Professor Ma and Yang's boyfriend arrived in time to save the danger. They take Percy to camp and train him, and they find a female soldier, Annabeth (Alexandra Daddario), to compete with her. After defeat, Percy, who touched the water, was activated and became an invincible soldier, and began a heroic journey in pursuit of lightning and fire. Faced with attacks from the snake girl Medusa and other gods and monsters, and the trouble of the King of Hades, Persephne, he only had 10 days left for self-redemption...