Things are about to go down in Star City! Spoilers ahead!
Arrow S4:E13 Sins of the Father Recap starts now!
At Thea's hospital bedside, Nyssa has made her offer to Oliver: The Lotus, which will cure Thea, in exchange for Malcolm Merlyn's life. Oliver tells her to kill Merlyn herself, that she needs to keep himself and Thea out of it. Nyssa tells him it was him that put the Demon's Head ring on Merlyn's hand, and Oliver realises that Nyssa doesn't believe that she can defeat him herself. Nyssa tells him that she has no choice, and Oliver tells her that Thea is dying because of what her father did and she has every choice. Nyssa believes that Thea is dying because of what her father, Merlyn, did "I am only following events to their inevitable conclusion" she says.
Felicity is having coffee with her father The Calculator, blissfully unaware as to who he is. He tells her he left when she was a child, as the police and FBI where after him, and it wasn't fair on her or her mother. He thought he was doing what was best for them. She asks why he took so long to come back into her life. He explains that on a recent job he was beaten by a genius hacker, and calls her by her code name "Overwatch". Felicity realises he is The Calculator and goes to leave. He tells her that he is a vigilante hacker, just like she was in college, just like she is now. They have more in common than she thinks. He gives her some files that show some of his hacks and the good that they have done, in the hope that she will agree to getting to know him. She takes the flash drive and leaves.
At the Arrow bunker, Diggle, Laurel and Oliver discuss Nyssa's offer. Diggle and Laurel think that killing Merlyn is a fair exchange to save Thea's life. Oliver, however, says that even though he has done terrible things, he is still Thea's father. His own father was not a good person, and he would do anything to have him back. Oliver proposes an agreement between Nyssa and Merlyn, that he willingly give up being Ra's Al Ghul and pass the title to Nyssa, in exchange for the Lotus. He believes that Merlyn would do anything for Thea, and this way no one has to die. They agree that Laurel will talk to Nyssa, and Oliver will put the idea to Merlyn.
Merlyn and Oliver meet on a rooftop, and Merlyn expresses his disbelief in the "magic potion" and in the fact that Nyssa conveniently has it in her possession. "I've been holding off telling you this for years Oliver" he says, "You're very handsome, but not especially bright". "Bright enough to have checked, it's called the Lotus" replies Oliver. Oliver explains where it has come from and that they need to get it for Thea now, but Merlyn refuses to believe anything she says. But if it were true, he would do anything to save Thea's life. He tells him that he will do something on his own and to stop wasting his time on Nyssa Al Ghul's games.
Laurel tries to talk to Nyssa and asks what she is doing. "Protecting my birthright", replies Nyssa. They speak of all the terrible things Merlyn has done, Laurel has lost two people she loves at his hands and wants him dead. "But if you want Merlyn dead, then you have to drive that sword. If you can't or if you won't, then we need to draft a compromise." Nyssa accepts the terms of the offer, but tells Laurel that he will never agree, and if that's the case then she is prepared to wage war. War that will carry over on to Star City and the streets will run red with the blood of her enemies. She claps her hands and an army of assassins appears to surround them.
Back at the bunker, Felicity arrives and tells them about her father, meeting him and then finding out he's The Calculator. "I wish there was some sort of test I could do, that would prove he is who he says he is." she says. "A test is a good idea" replies Oliver. "For you and for us. I've got a way to bring Merlyn to the bargaining table".
Nyssa is training her army, when Oliver enters asking her for some proof that the Lotus will work. She gives him small sample that will improve Thea's condition, but not enough to cure her permanently. "It is only to provide the assurance Merlyn seeks," says Nyssa. "As I said, someone is going to die".
At the bunker, Oliver has arranged for Thea to be discharged from the hospital and is residing in the basement of the bunker, still unconscious. He and Merlyn go down to see her, and Diggle is waiting with the vial of the Lotus ready to add to her IV. "Let's see it", says Merlyn. They start the infusion and the wound on Thea's chest closes and she briefly rises to the surface of consciousness. Merlyn asks what Nyssa's terms are, and Oliver says she will exchange the Lotus for the ring, and the leadership. "When can we meet?" he asks, "Tonight" replies Oliver.
Felicity's mom Donna comes to visit her at the apartment, and can tell something is wrong straight away. Felicity tells her about her father coming to visit, and whether maybe he is not quite as bad as she made out? Donna tells her he is exactly that bad, believe what he says and the next thing you know you are hurt, broke and alone. "People don't change, even if you want them to", says Donna.
The arranged meeting takes place for the exchange, "I'm glad you've finally seen reason" Nyssa says to Merlyn, "Sadly, the only thing I have seen is your quick and speedy death" he replies. Merlyn's own army appears and Nyssa yells "Kill him!". They begin to fight and Merlyn soon gets the better of Nyssa. Outnumbered and outgunned, she calls the retreat, and her and her army turn to run. Oliver, Diggle and Laurel block Merlyn from following, and his goes out the way him came in. Looks like it's war.
There are already fights and bloodshed happening on the streets of Star City; Captain Lance shows them the carnage and tells them they need to do what they can to stop it. Diggle confronts Oliver and tells him he has to kill Merlyn, it's time to face reality. "You've been living in denial, holding onto hope with both hands that you don't have to give in to that hate. Use that hate, to do what needs to be done" he tells Oliver.
At Palmer Tech, Felicity is showing her father through the lab and telling him about their latest developments. He stops to examine a T-Sphere that Curtis Holt invented and is way beyond anything currently on the market. Her dad is suitably impressed and pleased that she is beginning to trust him.
Nyssa and Merlyn's fight ends up on the streets of Star City, Laurel tries to put a stop to the fighting but gets caught up in it. Some civilians get caught in the crossfire and Oliver and Diggle step in and fight off Merlyn's men. They catch up with Nyssa and Diggle fires a tranquilizer dart at her, knocking her out. They put her in the cell at the bunker, and Laurel tries to get her to tell them where the Lotus is. Nyssa refuses to help and Laurel tells her she is not acting like herself, but the way her father used to be. But he is now dead, and there is no reason for her to act this way.
Felicity arrives and tells Oliver that she set a test for her father by showing him the lab, and he left behind a device that collects all the data from the technology around it. He was trying to steal Palmer Tech's secrets, and Felicity says "I set a trap, and he flunked with flying colours". Oliver tells her what Diggle thinks about taking down Merlyn, and Felicity agrees. "We are in this mess because of him, on a million different levels", she says. "I know all this, but I'm still holding out hope that they have some chance, at some type of relationship. If I kill him, my sister never gets that chance." he replies. A security alarm goes off, and Merlyn is in the basement at Thea's bedside. That sneaky snook.
Oliver rushes down and Merlyn tells him the Lotus effect is wearing off, Thea will most likely die by sunrise. As her father it is his right to come and be by her side. "This has to end" says Oliver "No more games. You give Nyssa the damn ring!" He adds "A real father wouldn't let their child die, just to keep his hands on power." Merlyn replies "That is not what I am doing. What's unfolding here, is larger than I. And it is bigger than my daughter." He reiterates that the power of the League of Assassins, that they are a force of change, silently manipulating global events, and how he is not willing to put that power into Nyssa Al Ghul's hands.
"Let me ask you something" Merlyn continues, "If Damien Darhk came to you and told you to lay down your bow, let him finish his plan for Star City, would you do it? Even if it meant saving William's life?" Oh snap, he knows about Oliver's secret son. "I know everything about you Oliver, I'm Ra's Al Ghul. You would never sacrifice your city to save your son, and believe me when I tell you I am only making the same choice." he says. "I would look for another choice, and I wouldn't stop looking until there was a third option. What if you could have the Lotus and keep your ring?" Oliver replies. "Trial by combat."
On a rooftop, Nyssa and Merlyn prepare for their fight. At the last minute Oliver steps in and says as her husband (long story), he has the right to fight on her behalf. Nyssa is horrified that someone will fight instead of her, and Merlyn is pissed that he has chosen to defend Nyssa's life over his. They begin to fight, and Oliver quickly gains the upper hand. Merlyn fights him off, and shoots at him with a arrow. Oliver deflects it and takes Merlyn down. Merlyn will not admit defeat, and tells Oliver that the only way this will end is if Oliver kills him. Oliver raises his sword and brings it down. On his arm! Merlyn has gone all Jamie Lannister on us! Ouch!
Oliver removes the Demon's Head ring from Merlyn's severed hand and passes it on to Nyssa, making her the next Ra's Al Ghul. She gives over the rest of the Lotus, and he places the ring on her finger. The assassins in attendance all bow to her, as does her husband Oliver (looong story).
Once given the Lotus, Thea wakes and apart from feeling tired she is recovered. Oliver tells her that the Lotus worked, no more blood lust. Laurel helps her go and freshen up, and Felicity asks Oliver when he plans on telling her about Merlyn's hand, "Baby steps", says Oliver.
Felicity is working at Palmer Tech when her father arrives. She tells him she is about to head into a meeting and that she doesn't have time for him. He asks her what is going on, he thought they were getting somewhere with their relationship. She tells him how much she hated herself as a child, "I thought I was broken. That no one could, or ever would, love me. It's the only way a child can grow up when their father abandons them". He explains that he couldn't let his family live a life on the run, the police and the FBI would never stop looking for him. "There is only one part of your story that I know to be true, and that is that you are wanted by the police". Captain Lance enters with several other officers and they place him under arrest. Felicity leaves without a backwards glance.
Nyssa has requested a meeting with Oliver and Laurel, telling them that she has learned a great deal about herself. Merlyn arrives having also been ordered to attend, his arm bandaged and in a sling. Nyssa tells them that she has disbanded the League of Assassins and throws the ring into a fire where it melts. "No one will be held prisoner by my father any longer" she says and leaves. "I thought of you as a son once, Oliver", says Merlyn, "But that's not the reason why I'm not going to kill you. The reason you get to live is that because death would be a mercy compared to the debt I now owe you". "Don't you dare threaten me", says Oliver.
Back at the apartment, Oliver is having feelings of guilt over what he had to do to Merlyn. Felicity is having the same feelings about her father, and will never forget the look on his face. Oliver asks her what they are waiting for, why aren't they married yet? Things will be calm now, it's the ideal time. Felicity agrees and tells him a small wedding sounds perfect.
Merlyn arrives in his car for a meeting with Damien Darhk. Darhk tells him he has no power any longer, what does he have to offer him anymore? Merlyn responds with "I have some information that you might find of particular interest. I know who Oliver Queen cares about most in the world". Darhk says "So do I. We did a pretty good number on her over the holidays" and goes to leave. "It's not Felicity Smoak", Merlyn says, stopping Darhk in his tracks. "His son, William." Sheesh.