"The Janitor Always Mops Twice" is the sixth episode of the fourteenth season of the American television sitcom It's Always Sunny in Philadelphia.
It is the 150th overall episode of the series, and was written by executive producer Megan Ganz, and directed by Heath Cullens.
The episode is a parody of the noir genre, with its title being a reference to the James M. Cain novel The Postman Always Rings Twice (1934).
Charlie follows a trail of blood when Dee (Kaitlin Olson) enters Paddy's and informs him that Frank (Danny DeVito) has been diarrhea-poisoned and is staying at her place.
The next day, Charlie goes around, trying to find anyone with a grudge against Frank, when he sees Vince (Wass Stevens) bothering his girlfriend, the Waitress (Mary Elizabeth Ellis), and scares him off.
The next morning, Charlie wakes up to find Dee in his bed, pretending to be dead, and Dennis and Mac trying to blackmail him by framing him for murder.
The episode omits the usual opening credits, instead having period-appropriate font on the backdrop of Charlie's bloody handprint on the door to the men's toilets.
[1] The episode is a parody of the noir genre,[2][3] with its title being a reference to the 1946 film The Postman Always Rings Twice, itself based on the 1934 novel of the same name by James M.