Yūta Tsuda, a high school student, battles a compulsive mobile phone addiction. Separation from his device triggers severe anxiety and withdrawal symptoms, culminating in panic attacks. When his phone is confiscated during class, this compulsion drives him to immediately abandon school and pressure his mother for a replacement.

Seeking help at Irabu General Hospital, he encounters Dr. Ichirō Irabu. The doctor acquires a mobile phone specifically to text Yūta directly. During therapy, Yūta requests phone contacts from Mayumi, Dr. Irabu's nurse, only to discover she owns no mobile phone due to a lack of social connections. A pivotal moment strikes Yūta at a Christmas party where he realizes his peers exploit and mock his addiction.

This revelation prompts Yūta to systematically delete all contacts from his SIM card. He subsequently receives an invitation from Dr. Irabu and Mayumi to a Christmas gathering at the hospital. Following a vitamin injection administered by Mayumi, Yūta is visually represented as a pale blue woodpecker adorned with multicolored spots, symbolizing his psychological state.