1914 Doctor John Watson goes to the front to serve in the medical forces. He thinks that investigating crimes is a thing of the past, and does not know that the main test in his life is still ahead. In the trenches of Flanders, people die in the hundreds every day, but when Dr. Watson finds a body with very strange wounds and with a grimace of fear on his face, as if the deceased had seen something terrible before death, he realizes that this is not like an ordinary death from a bullet or gas. When more and more of these corpses begin to appear, Watson has to use the skills acquired over the years of helping Sherlock Holmes. In the midst of the carnage on the battlefields of World War I, he will have to do everything himself to find a killer who will stop at nothing.