Mason is Maddie's mischievous second cousin who she often catches snooping around the Mansion. He claims to know Maddie and that "his moms" have shared Maddie's secrets with him. Despite Maddie's confusion, she discovers that Mason is Deb's grandson, making him a member of her extended family. Mason's mature personality sets him apart from other kids, and he prefers socializing with adults. Maddie is intrigued by Mason's unconventional behavior, and she wonders about the secrets hidden within his family's history, especially since they recently moved to Hopewell Bay for Pearl Wu's job. Despite his troublemaking tendencies, Mason adds excitement to Maddie's life.