CREATE TABLE table_24259 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" FLOAT, "US viewers  ( millions ) " TEXT)

Who are the writers for the episode number in series 129?
SELECT "Written by" FROM table_24259 WHERE "No. in series" = '129'
SELECT "Written by" FROM "table_24259" WHERE "No. in series" = '129'