“You might want to close that window. There is an east wind coming,” humble sidekick John Watson, played by Martin Freeman, warns Sherlock Holmes’s older brother Mycroft, played by Mark Gatiss, and the audience that BBC’s prized show was about to change dramatically.

Added to Netflix on May 15, season four of “Sherlock” has broken the mold casted by the previous seasons in an action-packed mystery thriller. From emotional strain to intense plot twists to a willingness to kill off favorites, the newest three-and-a-half-hour long episodes are memorable and shocking.

Starting from the first episode, it is perfectly clear that “Sherlock” was not like other seasons. The addition of new villains such as Vivian, played by Marcia Warren, Culverton Smith, played by Toby Jones and the epitome of an obsessive serial killer, and Eurus Holmes, played by Sian Brooke and Sherlock’s forgotten younger sister, as well as a return appearance from Jim Moriarty, played by Andrew Scott, add an element of severity to Sherlock Holmes’s puzzles. He no longer is dealing with amateurs, but criminal masterminds who also possess his gift of intelligence.

Capitalizing on the charisma from previous episodes, this season is full of witty comebacks and monologues that strengthen the friendship of the “Baker Street Boys.” Although the setting of each episode is melancholy and serious, the personality of the characters persists as a comic relief for the audience.

One thing is certain: goodbye lovable detective show and hello whirlwind of erratic plot and dark themes. Based off the novel by John O’Hara, “Appointment in Samarra,” the theme surrounding Sherlock Holmes’s life is the realization that this appointment with death is inescapable, which not only hits home with audience members, but is far contrasted with the light-hearted tone they’re used to.