Around one million individuals worldwide become infected with HIV, the virus that causes AIDS, each year. To replicate and spread the infection, the virus must smuggle its genetic material into the cell nucleus and integrate it into a chromosome. Research teams led by Dirk Görlich at the Max Planck Institute for Multidisciplinary Science and Thomas Schwartz at the Massachusetts Institute of Technology (MIT) have now discovered that its capsid has evolved into a molecular transporter. As such, it can directly breach a crucial barrier, which normally protects the cell nucleus against viral invaders. This way of smuggling keeps the viral genome invisible to anti-viral sensors in the cytoplasm.