Calendar Girl, whose real name is Page Monroe, first appears in the episode "Mean Seasons," which touches on issues of ageism and body dysmorphic disorder.
Monroe was a famous spokesmodel for several major companies until she turned 30 and her employers announced they were replacing her because of her age. She then worked briefly on a sitcom until the network also let her go in favor of younger demographics. Unable to obtain steady modeling or acting work, she disappeared from Gotham City and was rumored to have undergone botched plastic surgery.
Years later, she reappears as the masked villain Calendar Girl to obtain revenge against her former employers, kidnapping each of them on the anniversary of the respective dates on which they terminated her employment.
Until she is apprehended, Calendar Girl never allows anyone to see her face. When she is finally unmasked by the police, devastated and humiliated, she begs them not to look at her face. A surprised Batgirl remarks, "She's beautiful," to which Batman replies, "She can't see that anymore. All she sees are the flaws."
Calendar Girl uses theme-based weapons for different holidays or seasons of the year, such as spring egg gas bombs (Easter), fireworks-shooting top hats (4th of July), and exploding carved pumpkins (Halloween). She also attempts to kill her three former employers with a scythe (Day of the Dead).