Aizawa Umi is a good-natured girl who is the youngest of three sisters that live together. Her oldest sister, 21-year-old Sora, is kind of pushy and intimidating, but it's clear that she loves her sisters. The middle sister, Riku, is cheerfully clumsy and enthusiastic about life. Riku and Umi attend high school together, where they both hang out with their friends and Umi tries to handle her crush on a male classmate. This 4-koma tells comedic stories about their everyday home and school life.