18-year-old Tsukasa joins SAI corporation's terminal service department after failing college exams. His job is to recover Giftia androids nearing expiration, working alongside Isla, a Giftia previously relegated to serving tea.

After failing his college exams, 18 year old Tsukasa Mizugaki is offered a position at the renowned SAI corporation due to his father's connections. SAI corporation is known for its production and management of androids that possess human emotions called 'Giftia'. Tsukasa's position is in the terminal service department where their main job is to recover Giftias that are close to their expiration - it is a graveyard in every sense. To make matters worse, Tsukasa is offered to work with Isla, a female Giftia who was never given any responsibility other than serving tea to coworkers.—Yatin Chawla

Plastic Memories takes place in a city in the near future, in which humans live alongside androids that look exactly like humans and have human emotion and memory. SAI Corp, the leading android production company, has introduced the Giftia, a new android model with the most human-like qualities of any model. The lifespan of a Giftia is 81,920 hours (roughly nine years and four months), and if they pass their expiration date, it causes personality disintegration, memory loss and outbreaks of violence. As a result, the employees of the Terminal Service (responsible for retrieving androids who are close to reaching the end of their service lives and erasing the androids' memories) must go to the owner of the Giftia and retrieve it. Those assigned to the Terminal Service work in teams consisting of a human (called a "spotter") and a Giftia (called a "marksman"). The story follows protagonist Tsukasa Mizugaki and a Giftia named Isla, both of whom work in SAI Corp's Terminal Service No. 1 office.