As hard as it is for scientists to develop new drugs, sometimes just getting the drug to where it needs to act is equally challenging. Nowhere is this more true than in the brain, where blood vessel walls are tightly knit, keeping most large molecules from seeping out of the bloodstream and into brain tissue. This blood-brain barrier is a formidable obstacle to delivering certain types of treatments for neurological diseases, but Manjunath N. Swamy and his team at Harvard Medical School's Immune Disease Institute devised a clever way to sneak a drug through and insert it directly into brain cells.