The story begins in the future when Earth itself is no longer inhabitable by living creatures. Humans began their interstellar migration with space colonies. Vince and Hana work as researchers in the Cambrian Project. Together with the creature Pikaia, they seek the Lost Code, the key to restoring Earth, and aim to return to Cambrian-era Earth.

Second season of Pikaia!.

The earth shook. The sea roared. A far greater disaster followed. And then... There is a small house solitary standing by the seaside. A pigtail-braided girl is living there alone since that day. Mail is no longer delivered, but even this morning she's hanging out the laundry as usual. She's unaware that all around her, the clothes-pegs are quarreling, the pillow argues with the umbrella about the outside world, and the new toothbrush is unsuccessfully trying to be polite with the silent, old ones. Do things exist to be used until they are consumed or broken? Are they afraid of being thrown away once their life cycle is complete?

Asami Onohara is a seventeen-year old high-school student with a secret which has not been revealed to anyone: She is already married. Her husband, Kyosuke Ichimaru, is a Physics teacher in the same high school as her. However, even though they are officially a married couple, Asami's father forbids them to have any sexual contact until after Asami has graduated. Asami has to hide the fact that she is married to Kyosuke while trying desperately to further their relationship, and it does not help when there are so many interferences and obstacles from her father and other third parties.