When Evil Lurks is a chilling Argentinian horror film written and directed by Demi√°n Rugna. Set in a rural village plagued by supernatural infection, the story follows two brothers who discover a decomposing body possessed by a demonic presenceÑknown as a "rotten." Ignoring warnings and traditional purification rituals, they attempt to dispose of it themselves, unknowingly unleashing a wave of violent, contagious evil. As possession spreads rapidly, chaos and paranoia engulf the region. Combining psychological dread with shocking gore, the film explores themes of helplessness, tradition, and the uncontrollable nature of evil in a brutal, relentless descent into terror.