The shortest story ever about “It’s Always Sunny in Philadelphia” ran in the Daily News today, but it wasn’t written that way. But, many trees (and readers) were spared the entire story. Even the online version was truncated.

So here it is (it’s still not that long) in its entirety. Perhaps we’ll even share the transcript of the interview later.

Since its premiere two summers ago, “It’s Always Sunny in Philadelphia” has always played by its own rules, if it can be said to have any rules at all.

The comedy, which returns tonight at 10 p.m. on FX, concerns four friends, Mac (Rob McElhenney), Charlie (Charlie Day), Dennis (Glenn Howerton), Dee (Kaitlin Olson) – well, “friends” might be too strong a term, as they’re invariably happy to betray one another or think the worst of each other. Danny DeVito joined the cast last season as Frank, the father of two – and maybe three – of the gang, a guy whose arrested development may even be worse than the others’.

The group run – barely – a bar; in the course of the series, characters have organized Russian Roulette games, become crack addicts to cadge welfare checks and been accused, not wholly unjustly, of terrorism. Tonight, they try to profit off of a baby they find abandoned in a dumpster.

In an episode released online over the summer, Mac was suddenly and casually suspected by the others of being a serial killer.

“I’ve heard some criticism of that episode – people said it didn’t make any sense that they thought their friend could be a serial killer,” says McElhenney, who created and executive-produces the series along with Howerton and Day. He, along with DeVito, Howerton and Olson, are sitting in a barely air-conditioned trailer approximating their bar, only minus the booze, after sweltering for two hours in 100-degree heat signing autographs on the USC campus.

“Whoever thinks that doesn’t understand the show, because that’s the nature of the show,” McElhenney continues. “In this world, without any shred of evidence, they could instantly assume the worse.”

“Of their best friends,” Howerton adds.

“It’s fun for them, because they all had some selfish reason to think that,” Olson offers.

But the characters are perfectly comfortable with the fact that they are absolutely venal.

“I think our characters have extremely short-term memories, which helps,” Howerton says. “Episode to episode, which is fun to use. They genuinely have absolutely no idea.”

Olson adds, “We’re too busy thinking about ourselves to remember stuff. Any stuff.”

“We’re onto the next thing,” Howerton agrees. “We like to think of it as living in the moment.”

“Yeah, it’s really spiritual,” Olson deadpans.

“I get scripts that are so (expletive) far out,” DeVito marvels of the writers’ ability to one-up themselves. “I don’t think it’s more difficult for them. They bitch and moan constantly, but I think it’s second-nature for them to come up with these sleazy, scummy, lowlife views on the human race.

“There is something to be said for uniqueness,” DeVito continues, then, turning to the others, adds, “You don’t take the easy way out. The characters think they’re taking the easy road. But as writers, you always push yourselves into corners and work yourselves out. You’re in an era where you have to come across with the goods or get the (expletive) outta town.”

And yet, no one in the cast will condemn their characters’ behavior.

“I don’t think of them as bad, I think of them as retarded,” Olson says.

McElhenney interjects, “Sad…”

“Sad, and insecure and self-serving,” Olson continues.

“They’ve very insecure,” Howerton agrees.

“Really just pathetic,” McElhenney adds. “I kind of feel sorry for them.”

“I want to hug all of them and bring them over for dinner,” Olson says wistfully.

McElhenney brings her back to Earth: “But they would just ruin your life.”

And the riffing give Howerton an idea for an episode.

“Someone might recognize these characters and feel sorry for them and really genuinely try to help them,” he says, “and then they’d just ruin their lives.”

- "It's Always Sunny in Philadelphia:" 10 and 10:30 tonight, repeating at 11 and 11:30 tonight; also midnight Sunday and 11 p.m. Monday, FX.