As the first season begins, FBI Special Agent Olivia Dunham is called in to investigate a mysterious outbreak that nearly kills her partner. The only person with any answers is an institutionalized scientist, Dr. Walter Bishop who can only be released under the care of his estranged son. Together, the three discover that the answer to this mystery is only a small piece of a much larger, more shocking truth.

Holmes e Watson fizeram um acordo mutuamente favorável com Shinwell Johnson, um ex-condenado que oferece seu conhecimento do submundo da cidade em troca de aprender a ser um informante eficiente do FBI. A aliança do trio termina quando Shinwell agride Holmes depois que este e Watson descobrem que Shinwell cometeu um crime até então não esclarecido.

Holmes intenta rehacer su vida tras su ataque a Oscar y posterior recaída. Debido a sus acciones violentas, la asociación de Sherlock con Watson y su consultoría con la policía de Nueva York están en peligro. Mientras aguardan noticias de si se enfrentará o no a cargos criminales, el caso de una mujer desaparecida presuntamente asesinada por su marido por sus tierras llega a sus manos, justo a tiempo para distraerlo de la inminente llegada de su distanciado padre, el señor Morland Holmes.

La tercera temporada de Elementary comenzó el 30 de octubre de 2014 y finalizó el 14 de mayo de 2015 con un total de 24 episodios.

David Callaway tries to piece together his life in the wake of his wife's suicide and has been left to raise his nine-year-old daughter, Emily on his own. David is at first amused to discover that Emily has created an imaginary friend named 'Charlie', but it isn't long before 'Charlie' develops a sinister and violent side, and as David struggles with his daughter's growing emotional problems, he comes to the frightening realisation that 'Charlie' isn't just a figment of Emily's imagination.

La segunda temporada de Elementary comenzó el 26 de septiembre de 2013 y finalizó el 15 de mayo de 2014 con un total de 24 episodios.