Alex Witwicky is Sam Witwicky's baby sister. Alex is a very innocent and intelligent girl,even exceeding her big brother's intelligence,though she still remains innocent and a very curious girl,eager to find many more,that she hope she can learn,unlike her brother. She is only 5 years old, yet she beat her big bro! Sam always have Alex in his sight,like his,her own daughter,for crying out Loud! So what happens when she meet many unexpected people?