Retsuko is a personified little panda, 25 years old, single, working in the accounting department of a Japanese trading company. Faced with constant setbacks from aggressive superiors to annoying colleagues every day, Retsuko goes to karaoke bars every night to sing death metal to vent her emotions. After 5 years of daily work, her relationships with various colleagues began to change and gradually began to improve in ways that could change her life... Or worse.