As Moira (Susanna Thompson) returns to Queen Consolidated over Isabel Rochev‘s (Summer Glau) concerns, Oliver (Stephen Amell) investigates a break-in by one of Brother Blood‘s (Kevin Alejandro) enhanced soldiers (Graham Shiels) and Arrow gets one of its most prestigious guest-stars yet when a criminal scientist from Central City named Barry Allen (Grant Gustin) arrives in town to investigate the odd case. As Barry and Felicity (Emily Bett Rickards) work (and make goo-goo eyes) together, Oliver has Diggle (David Ramsey) look into the jumpy young scientist who hasn’t been completely honest with his personal reasons for coming to Starling City.
The theft of the centrifuge and meeting the impossibly-strong killer confirm Oliver’s fears that the super-soldier serum Dr. Ivo (Dylan Neal) was searching for on the island has made its way to Starling City. The flashbacks to the island involve Oliver, Shado (Celina Jade), Sara (Caity Lotz), and a quickly fading Slade Wilson‘s (Manu Bennett) discovery of the sub and the serum and Oliver’s first experience with someone exposed to the drug.
In the episode’s B-story Sin (Bex Taylor-Klaus) enlists the help of Roy (Colton Haynes) and Thea (Willa Holland) to search for a missing friend. When Oliver discovers his search is tied to the super-soldiers Green Arrow attempts to keep him from harm (even going so far as to shoot the young man in the leg). The episode also gives us Moria’s failed attempt at returning to life as usual but a much more successful attempt at standing up to Malcolm Merlyn (John Barrowman) by offering a single name that stop Merlyn’s demands – Ra’s al Ghul.
Although I still rebel against the idea of Barry Allen having dark hair, “The Scientist” does a good job introducing the character as well as his backstory (and even teases us with Barry playing with a rack full of chemicals on a stormy night). I’ll still withhold final judgement on the casting until I see him in the suit, but Gustin passed the first test (even if his version of the character is a little more goofy than I expected). The action-packed episode moves the show into next week’s mid-season finale, and some dangerous territory involving Ollie getting suped-up?, which should feature Barry Allen’s attempts to save Oliver’s life, the first confrontation between Green Arrow and Brother Blood, and (finally!) a mask for our hero under his hood.