Watch Someone's Knocking at the Door (2009) HD Full Movie Free on SolarMovie. Watch Someone's Knocking at the Door (2009) online free. Returning to the medical school where they were test subjects decades ago, a pair of outrageously tw...Returning to the medical school where they were test subjects decades ago, a pair of outrageously twisted serial killers use shockingly brutal sex acts to start killing off a group of drugged-out med students.