The Goddess Venus is jealous of the beautiful human girl Psyche and blames her pet unicorn, Unico, as Psyche's source of good luck that keeps her from the harm of the goddess' cruel intentions. Unico has the amazing power to make anyone he meets happy. Whether it's because of his personality or the powers of his horn, no one knows. Venus has Unico banished, and the West Wind now takes Unico from one place and time to the next. Taken to a heavily polluted city, Unico meets a sickly girl named Chiko who is suffering because of the pollution of a nearby factory that darkens the entire sky. Unico then is determined to cheer her up, cure her, and destroy the nearby factory.

When Unico, a young unicorn, is banished from his family by a pantheon of manipulative gods, his powers of joy and happiness are tested as he explores the lands with his friends Beezle and Katy.

A young unicorn named Unico must fight an evil magician and save everyone who's trapped under his spell.

This is the fourth original animated piece for the Tezuka Osamu Animation theatre that takes up Tezuka Osamu's message of "Saving our Fragile Earth" as its theme, and together with Unico's adventures commemorates the theatre's first anniversary. Unico, a unicorn's child, has dropped down from heaven. During his journey on the north wind, he meets Tsubasa, a tree boy who can speak. The Earth has become totally ruined to the extent that no creature can live there, because humans have drained it of all resources and destroyed the environment. Unico and Tsubasa go on a journey to find a way to make the Earth inhabitable again. They finally meet the Sphinx and the "time fairy" at the end of their hard journey. They decide to go back to the past and prevent humans from taking the wrong path. However, they can stay in the past for only five minutes. Will they be able to alter the future of the Earth in such short time? Their adventures to restore the Earth begin...