VIDEO: Sneak Peek - Tonight's Episode of CBS's ELEMENTARY

Related: ELEMENTARY, previews & teasers

On tonight's episode of the CBS drama series ELEMENTARY titled, 'The Leviathan,' Sherlock is called in to investigate when a supposedly uncrackable bank vault called "The Leviathan" is breached. Meanwhile, Joan is pleasantly surprised when Sherlock meets her family and defends her choice to become a sober companion. The episode airs Thursday, Dec. 13 (10:01-11:00 PM, ET/PT) on the CBS Television Network. Get a sneak peek below!

ELEMENTARY stars Jonny Lee Miller as detective Sherlock Holmes and Lucy Liu as Dr. Joan Watson in a modern-day drama about a crime-solving duo that cracks the NYPD's most impossible cases. Following his fall from grace in London and a stint in rehab, eccentric Sherlock escapes to Manhattan where his wealthy father forces him to live with his worst nightmare – a sober companion, Dr. Watson.

A successful surgeon until she lost a patient and her license three years ago, Watson views her current job as another opportunity to help people, as well as paying a penance. However, the restless Sherlock is nothing like her previous clients. He informs her that none of her expertise as an addiction specialist applies to him and he's devised his own post-rehab regimen – resuming his work as a police consultant in New York City. Watson has no choice but to accompany her irascible new charge on his jobs.

But Sherlock finds her medical background helpful, and Watson realizes she has a knack for playing investigator. Sherlock's police contact, Capt. Thomas Gregson, knows from previous experience working with Scotland Yard that Sherlock is brilliant at closing cases, and welcomes him as part of the team, which includes Detective Marcus Bell, a top-notch investigator with sharp intuition and formidable interrogation skills. Although initially skeptical of Holmes and his unorthodox methods, Bell begins to recognize Sherlock as an asset in their investigations. With the mischievous Sherlock Holmes now running free in New York solving crime, it's simple deduction that he's going to need someone to keep him grounded, and it's elementary that it's a job for Watson.