She first started as serious, hardworking, and the school principal. She was first seen when she caught Scott Calvin's son, Charlie, for defacing the walls of the gymnasium from the skylight. Initially she was going to suspend Charlie but was swayed by his father suggested that he do community service as punishment.
After a few failed dates, Scott finds himself falling for Carol. He accompanies her in a sleigh to her school faculty Christmas party, which turns out to be dull and boring.
He makes a special presentation to Carol, and, with his last remnant of magic, wins her over and they kiss passionately.
However, when Scott explains his reason for dating her as Santa Claus, Carol balks, believing that he is mocking her childhood (where she was teased for believing in Santa) until Charlie manages to convince her by showing her his magic snow globe.
He goes after Toy Santa, who has already left with the sleigh, riding Chet, a reindeer-in-training, and they both battle over the reindeer. With an army of elves, Carol, Bernard, Charlie, and Curtis lead a snowball war to overthrow the toy soldiers.
During the battle, Toy Santa and Scott accidentally cause the sleigh to crash back into the village (as well as crashing on the rest of the toy soldiers). Toy Santa is forcibly restrained by the elves and is reduced to his normal six-inch height.
Scott marries Carol in a ceremony presided over by Mother Nature herself.
He transforms back into Santa, and Christmas proceeds as it always has and he and Carol have a three-month honeymoon to go on the next day.
In addition, Charlie reveals the truth to Lucy that he is the real Santa Claus.
Carol is now pregnant with her and Scott 's child. Carol has adapted to being Mrs. Claus and is happy with their unique life.
While content with Scott, she expresses sadness that she misses her parents who she has not seen since she became Mrs. Claus. As a result, Scott goes to Chicago with the Sandman (under the nickname of "Sandy") to take them to the North Pole.
Due to the "Secret of Santa", Bud and Sylvia are under the impression that they have arrived in Canada, rather than the North Pole. They are unaware of Scott and Carol's true identities, and simply believe Scott to be a toymaker. Carol plays along.
After arriving, Bud and Sylvia meet Jack Frost, whom they are told is an actor portraying him in their winter show. The two were frozen by him and were left this way for a majority of the rest of the film. Bud and Sylvia are later freed when they are warmed up by everyone. The pair also learned that they were wrong about Santa Claus not existing when it turns out their son-in-law Scott is Santa and they are amazed by this news. They also become grandparents when Carol gives birth to her son.