After saving their newly found demolition business from Foreman Spike in MARIO AND LUIGI'S WALL-TEARING JOB 2 (2024), Mario and Luigi's have become the Mushroom Kingdom's top demolition services, and heroes known country-wide. Being alerted of a breakout on Prison Island off the Mushroom Coast, the brothers set off locked and loaded to go face to face with Shadow, a mysterious new adversary with powers unlike anything anyone has seen before.