A salaryman meets a high school student named Ai by chance on the train. After that, the two begin to see each other every Monday morning, and he acts as her bodyguard on the crowded commute, keeping gropers away while they talk. Their time together is short, but they grow closer and learn about each other's lives. To help him face the Monday blues, Ai gives him small gifts to keep him going. Other girls who share a certain attractive trait also brighten the start of the week for the men around them. Adapted from illustrations Himura Kiseki posts on Twitter every Monday, this twelve-episode ONA mixes slice-of-life moments with ecchi content.