Back alleys are rife with secrets, leaving dwellers to fend for themselves with limited resources. Akame is one such inhabitant - a twenty-year-old who seems much younger than he really is - who has been taught to steer clear of others. With a heart closed off from the world, he lives a lonesome existence. But when Mashiro, a cat-like girl in search of answers, enters his life, everything changes. Though her motives are unclear, one thing is certain: she adores Akame.
Initially irked by Mashiro's constant presence, Akame tries his best to push her away and continue his solitary routine. However, Mashiro won't let him be easily cast aside. As they spend more time together, Akame slowly begins to shed his resolute exterior and learns the importance of friendship. Thus, the story of Akame and Mashiro's life in the back alleys begins - a tale filled with warmth and heart.