The CW has released a new TV spot for the Arrow Mid-Season finale entitled The Scientist. The episode introduces Barry Allen (Grant Gustin) (aka The Flash), who will soon get a series of his own. Check out the action, and then read on to find out what will happen in this anticipated episode.

In the episode, 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 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 takes a liking to Barry, which doesn't go unnoticed by Oliver. Sin (guest star Bex Taylor-Klaus) asks Roy for help when a friend of hers goes missing. Roy is surprised when Thea 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.