Complete story — includes the ending
A bomb explodes in the office of a website design company, killing two and injuring eleven. The first suspect is someone who called a pager that triggered the bomb, but he just misdialed the number. The bomb is four years old, leading to investigation of the company that occupied the premises at that time. That turns out to be a high-powered public relations company. It received threatening letters from the ELM, an eco-terrorist group which bombed other companies, in 2008. However, this bomb did not use eco-friendly compounds, unlike the explosives the ELM used. The bomb was planted in a wall of the office of Pradeep Singh, a high-performing executive who went missing that year. Sherlock finds Singh's corpse hidden behind a wall of his house. Singh taped his encounters with prostitutes, one of them being the public relations company CEO Heather Vanowen. Vanowen financed her education and the startup of her company through prostitution. Singh was blackmailing her. When the bomb failed to go off, she shot him. Joan encourages Sherlock to choose a sponsor before she leaves.
Sources and content license
Source and revision history · Adapted from Wikipedia contributors, List of Elementary episodes. HTML formatting and reference markers removed. · Content license