Set in the near future, Akira Mizutame is a brilliant young scientist who developed Salt, a robot designed to assist people in their daily lives. He finds himself at a dead end following a series of failed inventions. When a friend suggests he could "power up" his personal life by creating a girlfriend, he develops an artificial partner, "No. 0," who quite literally becomes his girlfriend. Torn between her programmed emotions and her own evolving feelings, No. 0 faces an emotional conflict. Will love blossom between her and Akira, who is unused to connecting with others, or...?