Though the Flash will now make his CW debut in a standalone pilot episode, Grant Gustin, who will don the scarlet and gold, makes his first appearance as police scientist Barry Allen on this week's "Arrow." In an episode titles "The Scientist," Allen journeys to Starling City to aid in the investigation of some strange murders which bear some striking similarities to those he's looking into in Central City -- raising suspicion from Oliver Queen who quickly surmises there's more to Allen than meets the eye.
BARRY ALLEN COMES TO STARLING CITY — A seemingly impossible robbery at Queen Consolidated’s Applied Sciences Division brings Central City police scientist Barry Allen (guest star Grant Gustin) to town. Citing a similar case back home, Barry offers to help Oliver (Stephen Amell) and team with the investigation. Oliver senses there is more to Barry than meets the eye, but he’s distracted by the similarities between this current case and something that happened on the island. Meanwhile, Felicity (Emily Bett Rickards) takes a liking to Barry, which doesn’t go unnoticed by Oliver. Sin (guest star Bex Taylor-Klaus) asks Roy (Colton Haynes) for help when a friend of hers goes missing. Roy is surprised when Thea (Willa Holland) not only encourages him to help, but joins the search. Unfortunately, Sin’s friend is connected to Brother Blood (guest star Kevin Alejandro), and their search ultimately gets one of them seriously injured.
"The Scientist" airs Wednesday at 8PM on The CW.