Sherlock (Jonny Lee Miller) and Joan (Lucy Liu) are embarking on a new personal mission in Season 5 of “Elementary.”

In an interview with TVLine, “Elementary” executive producer Rob Doherty said that the crime-solving duo will be trying to reform an ex-con when the series returns in October.

“While this is a crime-based show, and we’ve met a lot of criminals, we’ve never really stopped to take the time to get to know and maybe even reform one,” Doherty told the news outlet, before revealing that the show’s lead characters will try to reform Shinwell Johnson — a new recurring character played by “True Blood” alum Nelsan Ellis.

“Sherlock and Joan will go into a relationship with Shinwell with the best of intentions,” the exec producer said. “But they’ll find it’s a very different kind of experience” working with an former prisoner.

TVLine reported last month that Shinwell — a character created by Sherlock Holmes author Sir Arthur Conan Doyle in his 1924 short story, “The Illustrious Client” — will first appear in the Season 5 premiere, which finds Sherlock and Joan joining the NYPD manhunt for a serial bomber who is active again after going dormant for six years. During the investigation, Joan seeks help from Shinwell, who is trying to get his life back in track after a long prison stint on drug charges.

According to the synopsis for Season 5, Episode 1, titled “Folie a Deux,” obtained by KSiteTV, Shinwell and Joan have known each other for a long time since she saved his life once when she was still a surgeon. After the season premiere, Ellis is set to appear in at least more two episodes.

In his latest interview with TVLine, Doherty also assured fans that Captain Gregson (Aidan Quinn) and Detective Bell (John Michael Hill) will get their due next season. “We're looking to advance both of those characters down certain paths,” he teased.

“Elementary” Season 5 premieres Sunday, Oct. 2 at 10/9c on CBS.