Mark Cain Mystery Novels - The literary works of Jason King (Peter Wyngarde), a successful mystery novelist on the espionage dramas DEPARTMENT 'S'/ATV/ITC/1969 and JASON KING/ATV/ITV/1971-72. His novel titles included High Fashion Murder and Two Plus One Equals Murder. Jason King was also one of three special agents working for Department 'S', a branch of INTERPOL. He helped solved each of his cases as if they were a plot for one of his novels.