In Scallywag: In the Lair of the Medusa, a mysterious evil has begun to plague the good citizens of Gosling valley. Livestock is vanishing, people are cowering in their homes, and telemarketers keep calling during the dinner hour. Even worse, the valley's supply of mushrooms is suffering, and for the valley mushrooms are life. Providing everything from shelter to sustenance, from magic to medicine, the shroom supply must flow once more!

In the tradition of NetHack and Rogue, players control a single character, Rapius the mighty farm laborer, in his quest to defeat the forces of darkness and become the savior of Gosling valley (and its shrooms!). Rapius, who begins his virtual career with barely a rag to wear, must penetrate eighty levels of darkness, growing in power with each denizen of the dark slain, each newly acquired trinket, and every mushroom consumed, until at last he meets his final foe, the dreaded Medusa!