The CW has officially revealed the promo for the season two finale of "Arrow" which you can checkout in the player below. Titled "Unthinkable," the episode is described as follows:
"Slade moves forward with his plan to kill one more person in Oliver’s life. While Oliver has fought all year to be more than the killer he once was, when Slade kidnaps someone close to Oliver’s heart, Oliver is pushed to the edge and realizes sometimes it takes doing the unthinkable to stop the monster. Meanwhile, Diggle takes on Amanda Waller (guest star Cynthia Addai-Robinson) with a little help from some friends, and Thea turns to Roy in her time of need."
Directed by John Behring with story by Greg Berlanti and teleplay by Marc Guggenheim & Andrew Kreisberg, "Unthinkable" is set to air May 14. "Arrow" airs Wednesdays at 8 P.M. ET/PT on The CW.