Jessica is a character from Halloweentown High.
After Marnie, Dylan, Sophie, Gwen and Aggie permanently open the portal between the human realm and Halloweentown, Marnie suggests to the Halloweentown Council that several students from Halloweentown be allowed to attend high school in the human realm. Jessica is a werecat chosen to be one of these students, alongside an ogre named Chester, a troll named Natalie, a wood nymph named Nancy, a witch named Cassie, a warlock named Ethan, a gremlin named Bobby, a zombie named Zachary, and a werewolf named Pete.
Upon arrival at her new school, Jessica is provided a disguise that hides her identity as a Werecat and is told that she is a foreign exchange student from Canada - though she, like many of the other Halloweentown students end up spending most of her time in apart from the rest of the student body. This prompts Marnie to encourage everyone to get involved in extracurricular activities in order to socialize.
During a visit to the local mall, Jessica is offended by the portrayal of creatures at a Halloween store, something that leads to Ethan picking a fight with a couple of guys saying that everything related to Halloween is for freaks. During the scuffle, Edgar Dalloway floods the scene with purple smoke, allowing Ethan to plunge an iron dagger into one of the pumpkins in the display as his father had told him. Once Aggie clears the smoke, it reveals Jessica and the other students for what they really are, prompting a hasty retreat back to the Piper-Cromwell family home. Following Cassie's kidnapping at Edgar's hand, many of the Halloweentown students returned home - including Jessica - with only Pete, Chester, Natalie, and Ethan remaining.
After the portal to Halloweentown is closed by Edgar, it is promptly reopened by the Halloweentown Council after Chester, Pete, and Natalie reveal themselves and are accepted by their fellow students; thus proving that humans really have changed. Then, Jessica returns to the human real alongside Gwen, Cassie, Bobby, Zachary, and Nancy and the Halloweentown Council captures Edgar within a Witch's Glass. Declaring peace between the two realms, the Halloweentown Council takes their leave, allowing Jessica and the rest of Halloweentown to traverse between the two freely.