While Arrow fans wait with anticipation for the next episode, a sneak preview was released Wednesday.

Scenes from the mid-season finale and eighth episode, titled The Scientist, reveal that the upcoming episode is definitely full of action. In the preview, Central City's Barry Allen (played by Grant Gustin) comes to the area after Queen Consolidated's Applied Sciences Division is robbed. Allen claims he worked on a similar case in his home town, but Oliver (Stephen Amell) feels as if there's more to his story that he's hiding. However, Felicity (played by Emily Bett Rickards) has some sort of attraction to Allen, which Oliver doesn't hesitate to notice as well.

In another storyline, Sin (Bex Taylor-Klaus) goes to Roy after her friend suddenly disappears. One of them gets badly hurt during their search. It's later revealed that her friend is linked to Brother Blood.

Don't miss the mid-season finale airing Wednesday, Dec. 4 on CW at 8/7c.