John Larroquette
John Larroquette’s Jenkins will swap bodies with a stranger in the all-new episode of “The Librarians.” Pictured: The Hollywood actor attending the 78th annual Drama League Awards Ceremony and Luncheon at the Marriott Marquis Times Square in New York City on May 18, 2012. Photo by Mike Coppola/Getty Images

When “The Librarians” Season 4 returns to TNT this week, fans will see a different Jenkins (John Larroquette). The cantankerous caretaker of The Library will apparently swap bodies with a stranger, causing confusion to Eve Baird (Rebecca Romijn) and the other Librarians.

A sneak peek at “The Librarians” Season 4, episode 10, titled “…And Some Dude Named Jeff,” shows Baird and her team heading to the Library for their new mission. When Baird calls Jenkins and asks the latter to bring out a door, a different person (guest star Andrew Caldwell) shows up to follow the command.

For some reason though, Baird, Ezekiel (John Kim), Cassandra (Lindy Booth) and Jake (Christian Kane) seem to be not at all surprised by the difference in Jenkins’ form. The teaser then jumps to a scene showing Jenkins realizing that his soul was transferred to the body of a 28-year-old slacker, named Jeff.

A voiceover then reveals that the real Jeff switched his body with Jenkins’ on purpose. The all-new episode’s synopsis appears to suggest that the real Jeff may have the intention of destroying The Library, so the real Jenkins will have to stop him. But this won’t be easy Jenkins because he doesn’t have the right biometric data to gain access to the secret facility.

Another promotional clip shows Jenkins being denied access into the Library because his handprint and voice do not match anything on the database. When he tries to communicate with Baird via the surveillance camera, the Librarians won’t recognize him and they will even jump to the conclusion that a stranger is desperately trying to enter the Library.

Upon realizing that the video feed being projected to the headquarters inside the Library does not have audio, Jenkins comes up with a cardboard sign that says, “I Am Jenkins. My body has been switched.” Unfortunately, the fake Jenkins interrupts the Librarians from seeing what the real Jenkins wrote and convinces them to just focus on their new mission.

The synopsis mentions that in order for Jenkins to correct the body switch, he will need a team, but it isn’t going to be Baird and the rest of the quarter. Jenkins will instead have to enlist Jeff’s hapless Dungeons & Dragons friends to fix the problem.

“The Librarians” Season 4, episode 10 airs Wednesday, Jan. 24, at 8 p.m. EST on TNT.