One day, while the Morita family is enjoying a holiday camp, a mysterious man in a cape, Knockman, appears before them. Knockman unleashes their powers and draws out their superpowers, transforming the Morita family into "Knockers," people with extraordinary abilities. Knockman then asks them to protect Earth from the impending threat of space monsters, and the Morita family becomes Knock 5, ready to confront the space monsters. However, Knock 5 faces a harsh life, having to hide their identities while fighting the space monsters and suspending their personal lives.