Oliver makes his choice in the next episode of "Arrow" season 4, which is titled "Sins of the Father." The episode will demonstrate just how far he is willing to go when it comes to his sister Thea.

In the previous season, Oliver agreed to become the heir to the demon in order to bring his sister back to life.

Now, he finds himself in the same situation, but this time he has to kill the new leader of the League of Assassins to save Thea.

In the previous "Arrow" season 4 episode, Thea was seen getting weaker; her health has been rapidly deteriorating. Nyssa arrived to tell Oliver that there's a way to save Speedy but he has to kill Thea's father, Malcolm, in order for him to get it.

The promo for the upcoming episode teases a showdown between the Oliver and Malcom, which confirms that Oliver has made up his mind.

A promotional image for the episode has also been released. It features Speedy with her head down and Malcolm in the background. The artwork bears the words "The sins of the fathers are revealed," alluding to the title of the next "Arrow" season 4 episode. It is also worth nothing that the tagline says "fathers," which hints at the involvement of someone else's dad.

The synopsis for "Sins of the Father" teases Malcolm helping his daughter survive. His solution, however, seems to not involve his own death.

"What's unfolding here, it is bigger than my daughter," he tells Oliver in the teaser.

At some point in the "Arrow" season 4 clip, Malcolm and Nyssa can be seen in a duel as well. In another sequence in the video, Nyssa can also be heard warning Laurel that there will be war.

"The streets of your home will run red with the blood of our enemies," she declares.

The synopsis teases that Laurel will be opening up to Nyssa, but there's no telling how this can affect Thea's chances of surviving. If there's anyone that can talk to Nyssa heart-to-heart, it's Laurel. Could she convince her to help them?

"Arrow" season 4, episode 13 "Sins of the Father" airs Feb. 10 at 8 p.m. ET on CW.