Dark River

S2 E4: The body of a man is found naked and emaciated under the rusted uprights of Aberystwyth pier. Pathology reports that the dead man’s stomach is full of pebbles and bottletops. Mathias’ investigation leads him to a newspaper article about four school-friends in the late 70’s that claimed to have seen a UFO in a field adjacent to their village school. Four friends who haven’t spoken in twentyfive years. But is there a link? Does the UFO story conceal a more sinister childhood secret?