"Big Top Dog" Robot wonderdog ARCHIE, along with his UNCLE PAUL, is spending the summer at the family cottage. Tagging along is family friend SYDNEY, who has hitched a ride for one sole purpose: to join the circus. As it turns out, THE MAGICAL MYSTERY CARNIVAL is passing through the rural town near the cottage and Sydney has secured himself an audition. Joining the circus is his lifelong dream. In town, Archie befriends eleven-year-old GREGORY, who is the son of the man who runs the carnival. Gregory confides in Archie that someone is stealing from his father and that the carnival is on the brink of bankruptcy. For his carnival audition, Sydney convinces Archie to be his "ventriloquist dummy". Archie reminds Sydney of RULE NUMBER ONE: "Nobody can ever know about my special skills". But, it's too late: one of the carnival members, LARA, has overheard everything. Of course, everyone is blown away by the two, and Sydney and Archie find themselves officially the newest members of the carnival. By the time Gregory figures out the culprit who is stealing from his dad is Lara, it's almost too late. She has absconded with the carnival money and has sequestered Paul's plane to fly her to safety. Gregory must team up with his newfound friend Archie to save the day...