For decades, the story of sleep and Alzheimer's has followed a familiar arc: disruption begets accumulation, accumulation begets loss. Yet a new study from the University of Pennsylvania quietly unsettles that narrative, finding that mice engineered to develop tau pathology actually learned better in late life after experiencing chronic sleep disruption in early adulthood. The brain, it seems, does not always follow the path we draw for it — and the immune cells quietly patrolling its corridors may be writing a different story altogether.