Eleven-year-old Martin (Emanuel Latanzio) falls in with the elderly mad doctor next door (Daniel Carrera), whose revolutionary age-reversing drug turns him into a schoolboy as well; adopted temporarily by Martin's credulous parents, the new boy causes havoc at school and eventually crosses swords with a malicious academic rival who's come looking for him. This low-budget kiddie comedy from Mexico aspires to the hip, candy-colored vibe of Robert Rodriguez's Spy Kids movies, especially in its genial parent-child relationships, but compared to its models, it's pretty short on invention. The meager special effects budget doesn't help: when an adult character turns into a child—the key imagery needed to sell the fantasy—director Jose Buil simply punts, cutting to a reaction shot. In Spanish with subtitles.