CREATE TABLE "series_4" (
  "episode" real,
  "title" text,
  "story" text,
  "adapted_by" text,
  "director" text,
  "airdate" text,
  "exists" text
);

Question: What was the title of the episode that martin worth wrote the story for?
SQL: SELECT "title" FROM "series_4" WHERE "story"='martin worth';