Hi no Tori 2772: Ai no Kosumozon plot
"In the year 2772, a young cadet is sent to capture a mystical universal Phoenix, which possesses the power to rejuvenate the drained Earth."
In the year 2772, the Earth and many of its colonies fell into disrepair. A little boy named Godo grows up lonely in a hermetically sealed and technically advanced room. His only companion is the female robot Orga who watches over him. When Godo is old, he is recruited and trained in a military camp. Impressed by Godo's abilities, his boss Rock sends Godo to capture the mysterious Phoenix, a mythical creature with the power of rebirth.