Fans anxious for "Elementary" to return for its fourth season got to hear a few teasers at this year’s Comic Con, when stars of the hit series spoke on a panel about several show themes, including Holmes' addition.

The last season ended with Holmes falling off the wagon and spirally out into the chaos of addiction. Johnny Lee Miller, who plays Holmes, hinted that his character’s latest relapse might not be his last one. Speaking of addiction, the actor known for playing a heroin addict in “Trainspotting," said, “A problem like that doesn’t ever go away in someone’s life.”

As reported by Entertainment Weekly, Miller added, “Drug addiction is something that can be handled … but the problem itself isn’t ever going to go away. It’s a storyline you can always go back to … It’s not a huge nemesis that is dealt with and then done with.”

Acknowledging the changes that would be coming to the show, Lucy Liu, who plays Joan Watson on the series, said that the relationship between Holmes and Watson, which had been tied up in Holmes' ability to stay sober, would now have to develop in "a much deeper manner.”

“I think the main thing is to billboard the fact that their relationship has developed outside the sober companionship,” the 46-year-old actress said.

On the production side of the series, Liu, who has been trying to get into directing for the last few years, will be getting behind the camera for an episode this season. Miller is all for his co-star's turn as director, saying, “It’s a wonderful thing to see someone begin to fulfill their dreams and ambitions and progress.”

“The care that she takes over that aspect of it … is very important to Lucy,” the 42-year-old English actor added.

Fans of the series have been wondering since day one whether Holmes and Watson would hook up. Speaking to IGN at Comic Con, Liu describes the platonic relationship of the characters as almost instructive, saying it’s good to “introduce people to a different way of seeing a man and woman on screen as partners.”

“Elementary” returns to CBS in November.