The detectives are on the trail of a thief whose interest in a rare map leads him to commit murder. Preview tonight’s Elementary season 3, episode 6.

“Terra Pericolosa,” or the “dangerous land” is what leads Holmes, Watson, and Winter to the case of the missing Brays Map on tonight’s episode.

Last Week on ‘Elementary’

With Watson off on her “sexcapade” in Copenhagen, Kitty and Sherlock are left to uncover an illegal diamond trade that led to the death of a local postage shop owner. Sherlock begins to sow seeds of distrust in Kitty when he discovers that Watson kept a rather lengthy manuscript of their time together entitled “The Casebook of Sherlock Holmes.” Feeling betrayed, Sherlock approaches Kitty with a nondisclosure agreement regarding their time together.

But Sherlock’s anger is a smoke screen for the bigger issue, why did Joan feel the need to keep the manuscript a secret from him? Over the course of their partnership, much to the dismay of Watson, Sherlock made every effort to keep the air clear between them. Even if that meant going behind her back and snooping. Hold on to that thought as Sherlock’s relationship with Kitty evolves this week.

Speaking of Kitty, she and the Captain had a heart to heart after his daughter revealed she was the victim of an abusive relationship. Kitty not only offers the Captain advice from her personal experience, but does what he cannot in his position as Captain. She eliminates the abusive male factor.

Related: Check out the stills from this week’s Elementary season 3, episode 6.

This week on ‘Elementary’

Joan is back and assisting on a case that involves a generous philanthropist, a missing map, and two dead bodies. While on the case, Sherlock, Joan, and Kitty work with a wealthy heiress, guest star Mamie Gummer, and dive into the world of cartographic crime. But what does this map of King James County, Virginia reveal that the causes such a stir?

Related: Elementary season 3, episode 6 sneak peek explores cartographic espionage

Tune in to Elementary season 3, episode 6, “Terra Pericolosa,” tonight at 10:00 p.m. ET on CBS.