Moshi Moshi? Watashi Smartphone desu ga Nani ka?

On a boy's birthday, he receives a high-performance smartphone in the form of a girl named Extra. After setting it up with a lip print authentication, they become inseparable. As a new student at school, the phone gains popularity by exchanging contacts with classmates through a dance feature, while the boy remains unnoticed. Extra reads messages aloud but does not display them, and her alarm function is ineffective. Despite these quirks, she helps the boy make friends and brings excitement to his daily life. The story follows their dynamic in a romantic comedy centered around a smartphone with a human-like presence.