Tsukasa Mizugaki obtains a job in the terminal service department of SAI, whose purpose eludes him. Upon his arrival, he is partnered with Aira, a Giftia android, and learns what it is that the terminal service department does for work.
Aira and Tsukasa's partnership appears to not be going well. When executing their tasks, they seem to fail even when faced with those that are easy, which raises the question of who is the problem.
At Terminal Service One, all marksman-spotter pairs are required to live together in order to strengthen bonds. In light of this, Tsukasa moves in with Aira. However, Aira seems ever distant when at home.
In a new case that Tsukasa and Aira have to handle, Souta, an orphaned child, has to come to terms with the fact that he will lose the only family he has left - Marcia, a Giftia who has been his sole caretaker since his parents' death.
A Giftia has moved from the jurisdiction of Terminal Service 3 to Terminal Service 1, prompting a marksman from the former, who is a friend of Eru's, to team up with Tsukasa and Aira. Later, they visit the carnival.
After hearing the news of Aira rejecting Tsukasa, the entire office is astonished. The truth behind this rejection is revealed to be Aira's uncertainty, leading to Michiru suggesting that she and Tsukasa live apart.
Due to the tension between Aira and Tsukasa, Kazuki dissolves the partnership between Aira and Tsukasa. Despite this, Tsukasa remains persistent that he remain partners with Aira.