Cody Cheon and Jenny Park were a happy couple who had first met while at Camp Half-Blood. After the two had gotten rather frisky one night and engaged in sexual intercourse, Jenny told Cody she was pregnant and together they moved into a nice apartment in New York. Months after they had moved into the apartment together, Jenny had given birth to a beautiful baby boy who they named Matteo. Only two weeks after Matteo was born however, Jenny got into a fatal car accident, leaving Cody to take care of Matteo.
Now being a single father, Cody took great care of Matteo. But after a month of Matteo being born, he was diagnosed with the same brain problem that Cody had when he was younger, as well as Mi-Young. But unlike Cody, Matteo seemed to have the same fate that Mi-Young had. With Matteo dying in Cody's arms, he took him to Ken and begged him to help. Ken then brought Cody to Olympus where they pleaded to Zeus to save Matteo. Zeus agreed to saving Matteo and turning him into a Storm Spirit, in exchange for Cody's freedom. Cody took Zeus' offer, and became an immortal servant to Zeus.
Zeus also accelerated Matteo's aging. Matteo aged seventeen years in only three years, and since nymphs stop aging once they are fully grown, Matteo seemed to have stayed at seventeen. Matteo grew up very rarely getting to spend time with Cody, he would only see him late at night or while walking around Olympus. However Matteo was also busy, as he had to spend time learning from Athena, who was forced into teaching Matteo basic knowledge.
Six years after, Cody got tired of feeding Zeus with grapes and cleaning up his bed when he and Hera had nightly sessions. Hebe, who sympathizes him because of her similar jobs, holds a feast in Mt. Olympus. In the midst of the party, the goddess sneaks both Matteo and Cody out of Olympus and into the Empire State Building elevator, granting them freedom.
However, as they emerge into the mortal world atop the building, a gang of vicious storm spirits whisked away Matteo into places who-knows-where. Seeing that Aeolus was responsible for the storm spirits' activities, Cody went for Aeolia to meet him. However, when he arrived there, he was just in time to see his son and the other spirits being released again by a wind nymph. With no idea on their destination, Cody seeked the help of his uncle Ken to find Matteo.
During Matteo's time with the rest of the storm spirits, he had been forced into joining them in killing innocent demigods who were getting in trouble. After killing a child of Hebe, who happened to be Calypso's lover, while on the island of Ogygia, Cody and Ken found Matteo, and they quickly saved him from the other storm spirits. Ken then told Cody to take Matteo back to Camp Half-Blood, after deciding to stay on the island to be with Calypso.
As they traveled for Camp Half-Blood, Hebe found out what Matteo and the other storm spirits did to her son. As such, she cursed Matteo by reverting his mind into that of a five-year old. Shortly after they arrived, Cody found a place for them to live in at the Nymph Sanctuary while still adjusting to his son's new behavior.