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...

天界からこぼれ落ちたユニコーンの子供、ユニコ。北風とともに旅する途中で、言葉をしゃべる木の少年、翼と出会います。地球は、人間が資源を使い果たし、自然を破壊したために、人間はもちろん、生き物の住めない荒れ果てた星になってしまいました。ユニコと翼は、地球を生き物の住める星に戻す方法を探すために、一緒に旅へ出ます。苦しい旅の果てにであったスフィンクスと時の妖精。彼らの力をかりて過去の地球へ行き、間違った道へ進もうとする人間達を救うことにしました。でも、過去へ戻れる時間は、たった5分。そんなわずかな時間で、地球の未来を変えることが出来るのでしょうか。ユニコと翼の大活躍が始まります。もう一度、地球を緑あふれる世界に戻すために。