Series by タイザン5

Tsubasa Ichinose, a middle school student, wakes up in a hospital with no memory after a car accident. His family—sister Shiori, parents Kakeru and Minako, and grandparents Kozo and Sachie—also suffer from amnesia due to the same incident. To rebuild their bond, they share fabricated memories, gradually growing closer. Upon returning home, they discover their house is in disarray, hinting at a darker reality about their family. Tsubasa grapples with unsettling clues, questioning the true nature of their relationships and past.

In 2016, an octopus-like alien comes to Earth from Happy Planet to spread happiness. He is helped by a fourth-grade girl and decides to repay her kindness. The girl lives with family troubles and suffers bullying at school. Wanting to bring back her smile, he uses the strange tools he brought with him to help her. His innocent efforts run into hardships he cannot understand, and the gap between his cheerful mission and her daily life drives the conflict.