Back alleys are filled with secrets, and their inhabitants are in a constant struggle to survive with the limited resources they have. One of these back alley dwellers is Akame, a self-proclaimed baby-faced 20-year-old. Having been taught to not associate with anyone, he lives in solitude, keeping his heart closed off from others. However, his reclusive way of living is suddenly disturbed when he meets the clingy but cute cat-like girl Mashiro. Who she is and where she comes from may be a mystery, but one thing is certain—she loves Akame.

Much to his annoyance, Akame is greeted by Mashiro every single day. He relentlessly tries to chase her away, attempting to return to his solitary lifestyle. Despite his endeavors, Mashiro persistently sticks to Akame's side. With her now being part of his life, Akame slowly learns to open his heart to others and realizes the importance of companionship. This is the start of Akame and Mashiro's heartwarming back alley life!