Stepsister from Planet Weird

Megan Larson (Courtnee Draper) is an ordinary 14-year-old girl whose life is turned upside down when her mother meets Cosmo Cola (Lance Guest), a strange but nice man who has an intelligent and awkward daughter named Ariel (Tamara Hope). As Megan tries to stop her mother's engagement with Cosmo, she discovers that Ariel and her father are actually aliens from Planet Zircalon hiding out on Earth. Despite their initial animosity, Megan and Ariel form an unlikely friendship as they work together to defeat the tyrannical emperor S'Vad (Tiriel Mora) and find love in the process.