Summoned by a vengeful sorcerer snake, an army of malevolent boars has invaded the peaceful haven of Riversplash Mountain. Only a few humble friends from the swamp dare to believe they can prevent the invaders from ravaging their fertile mountain. Farmer mouse Thrym, wise hedgehog Muspul, a father-and-son team of shrews, and the beautiful mouse maiden Olweena dangerously assume the masked identities of the Brave Tails, legendary, sword-wielding heroes of yore who originally rid their land of predators. But these small defenders will need more than masks and swords to stop this brutal onslaught – and the magic they seek is even more dangerous than the boars.