Every Monday, a regular salaryman named Oniisan guards high school student Ai-chan from harassers during their train ride. In this brief weekly routine, Oniisan and Ai-chan forge a close connection, delving into each other's worlds. Ai-chan boosts Oniisan's spirits by gifting him small tokens of encouragement, making his Mondays more bearable. Alongside Ai-chan, a group of girls, each possessing a captivating quality, bring joy to their male companions and coworkers as they navigate the challenges of the workweek.