Season 1

Kouki and the angel try to figure out the reason why the angel ended up in his house, but the two of them come up short.

Kouki and the angel go out to get food together, but the surroundings make the angel extremely uncomfortable.

Kouki's mom suddenly drops in, and Kouki fills in the angel on his past.

The angel realizes that Kouki is the only one who can see him, which leads to Kouki investigating the reason why fate brought them together.

After following a trail of evidence, Kouki and the angel gradually piece together the latter's former life.

In what little time they have left, Kouki decides to take the angel on a trip to do everything the latter always wanted to do.