Rebecca "Becky" McDougal is 11 years old. She is Ace’s weirdo younger sister. Becky is totally obsessed by aliens and is convinced Ace’s strange powers are the result of him being replaced by an alien impostor. She’s always snooping, spying and setting up elaborate schemes to try to catch “Alien Ace” out. Deep down though, she truly loves her brother... And she’d tell him so personally - if she ever finds the UFO that kidnapped him!