CREATE TABLE table_3918 ("Episode #" FLOAT, "Series #" FLOAT, "Title" TEXT, "Director" TEXT, "Writer" TEXT, "Original airdate" TEXT, "Viewers  ( millions ) " TEXT)

What episode in the series had 5.24 million viewers?
SELECT "Series #" FROM table_3918 WHERE "Viewers (millions)" = '5.24'
SELECT "Series #" FROM "table_3918" WHERE "Viewers (millions)" = '5.24'