This European-produced Western, inspired by Friedrich Gerstäcker’s novel, unfolds in a 19th-century town along the Mississippi River. The region is terrorized by a band of pirates led by the notorious Captain Kelly. These marauders reside on a river island, launching attacks on steamboats and trading rafts, seizing their goods and killing the crews. The local townsfolk and settlers are determined to stop the pirates’ reign of terror and bring down their audacious leader.