CREATE TABLE table_2404 ("Episode No." FLOAT, "Series No." FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Viewers  ( millions ) " TEXT, "Original airdate" TEXT)

Who wrote the episode that had 8.84 million viewers?
SELECT "Written by" FROM table_2404 WHERE "Viewers (millions)" = '8.84'
SELECT "Written by" FROM "table_2404" WHERE "Viewers (millions)" = '8.84'