The season finale of CBS’ modern take on Sherlock Holmes, “Elementary,” has its too-smart-for his-own-good sleuth battling his addiction demons.

The show, titled “A Controlled Descent,” is darker and more personal than previous episodes about socialite beekeepers and deadly hackers have been, as it deals with a friend and former sponsor of Holmes (Jonny Lee Miller) who has gone missing.

The troubled detective will wonder if Alfredo (Ato Essandoh) has been abducted or has simply relapsed. Whatever the scenario, Alfredo is in trouble, and it is the kind of situation that will test the detective's will to stay sober. As Holmes is occupied with another investigation, Watson (Lucy Liu) will work with the cops to find Alfredo.

As show creator Rob Doherty told TV Guide, the season finale will have Holmes keeping some "bad bad company." The dangerous individual on the scene “is someone we've seen before and is a threat to him," says Doherty.

Reconnecting with this person will be both a test to Holmes’ sobriety as well as a revelation of his dark past, illuminating a brutal side of personality.

In recent years, several contemporary adaptations of the Holmes myth have dealt with drugs and addiction, from extreme dalliances with booze and pills on the Hugh Laurie medical drama “House” to the Robert Downey, Jr. scene of hallucinatory closed room investigation in Guy Ritchie’s 2009 take on the Arthur Conan Doyle character.

However the drug use is played up in these Holmes adaptations, it was all less of a big deal in the books that inspired the shows.

As Dr Andrzej Diniejko notes in the introduction to his essay, “Sherlock Holmes's Addictions,” for the detective, who on occasion used cocaine and morphine to escape what he deemed “the dull routine of existence,” there was nothing so out of the ordinary about his drug use as at that time in Victorian England the “sale of opium, laudanum, cocaine and morphine was legal.”

Episode 24 of Season 3 of "Elementary" will air on CBS on May 14.