April 11, 1970
Appeared serially in "Play Manga" (Akita Shoten Publishing Co., Ltd.) as a complete story

Two guppies that love each other live in a tropical fish tank, but a cigarette butt dropped into the tank kills the two.
Mankind becomes extinct as a result of a nuclear war in 19XX, but two babies, a boy and a girl, grow up in good health inside a capsule made for a space trip that was displayed at an international exposition. The two fall in love. One day, they become curious about the world outside the capsule, and begin to wish to go out.