"The Scientist" is the eighth episode of the second season of the American television series Arrow, based on the DC Comics character Green Arrow, revolving around billionaire playboy Oliver Queen as he returns to Starling City, after having been shipwrecked for five years, and becomes a bow-wielding, hooded vigilante who sets out to fight crime and corruption.

Stephen Amell stars as Oliver, alongside Katie Cassidy, David Ramsey, Willa Holland, Emily Bett Rickards, Colton Haynes, Manu Bennett, Susanna Thompson, and Paul Blackthorne.

The episode also serves as a backdoor pilot to the spin-off series The Flash, with the introduction of guest star Grant Gustin as Barry Allen, who arrives in Starling City to personally investigate a superhuman-related crime.

"The Scientist" originally aired on The CW on December 4, 2013, and was watched by 3.24 million viewers according to Nielsen Media Research.

In a flashback to the island, Oliver and Shado find the serum, but when they inject it to Slade without the required sedative, his heart stops, just as Ivo arrives with his men.

[2] The episode also serves as a backdoor pilot to the spin-off series The Flash, with the introduction of Barry Allen, played by guest star Grant Gustin.

[6] The episode, along with the rest of the second season, was released on Blu-ray and DVD on September 16, 2014,[7] and began streaming on Netflix in the United States on October 8, 2014.

[10] Jesse Schedeen of IGN scored the episode an 8.5 out of 10, praising the emergence of super-powers and flashbacks but questioning Gustin's ability to hold his own.