Watch Marmaduke for Free: How to Stream the Movie Online at 123Movies. . Great Dane Marmaduke epitomizes the overgrown lapdog, with an irascible streak and a penchant for mischief that is tempered with a deep sense of love and responsibility for his human family, the Winslows. The new animation is set in the world of elite dog shows, rife divas, rivalries and slapstick comedy.