A pint-sized extraterrestrial lands on Earth and ends up separated from his parents. Lost and lonely, he befriends young Eric, who is immediately charmed by this little "Mysterious Alien Creature" and nicknames him "MAC." The two quickly become best buddies, but the problem is that no one will believe that Eric's fun new friend even exists...until MAC comes out of hiding and takes Eric, his family, his neighborhood and his world on a fantastical journey that will transform their lives forever!