The Great Marcusio is Marcus, a bumbling high school senior desperate to prove his magic chops to his family. Though Marcus struggles to master his dime store illusions, it's overcoming his annoying sister and doubtful parents which proves to be most difficult. When Marcus lines up a big magic gig for a young girl's birthday, his parents are thoroughly unimpressed, though he sees it as his next big break.

Pushed to his emotional limit, Marcus is determined to make the party a success. When he dares to perform a dangerous trick for the young party guests, will he unleash a power he never knew he possessed? And will it be enough to prove the doubters wrong?