Tonight's episode of "Arrow" -- "Sins of the Father" -- was full of ambushes. Nyssa ambushed Oliver by threatening to let Thea die if he didn't kill Malcolm Merlyn. Malcolm ambushed Oliver when he backed out on the deal to hand over the ring of Ra's al Ghul to Nyssa. The Calculator ambushed Felicity when he told her that he was her father and that he knew she was a vigilante hacker. Lastly, Malcolm ambushed Oliver by aligning with an enemy so ferocious, he would put in danger the person who mattered the most to Oliver, his son William.

Firstly, Nyssa (Katrina Law) ambushed Oliver (Stephen Amell.) Nyssa showed up out of the blue with a mystical cure for Thea (Willa Holland,) a healing flower called "the lotus." Oliver was pleased that Nyssa would provide a cure, but the cure came with a price. Oliver would have to fight and kill Malcolm Merlyn (John Barrowman) if he wanted the lotus from Nyssa. This ultimatum put Oliver in a terrible position. Not only had he sworn off killing, but he could not in good conscience kill his sister's father. Not after Thea lost her first father, Robert Queen, and her mother, Moira Queen. Killing Malcolm would make Thea an orphan, and Oliver couldn't bring himself to do that.

Oliver devised a plan that would require both Nyssa and Malcolm's agreement. Nyssa would give the lotus flower to Oliver if Malcolm surrendered to her the ring of Ra's al Ghul. The ring would grant Nyssa the power to rule the League of Assassins, and Malcolm could escape with his life. They both agreed to this arrangement, but when the time came, Malcolm ambushed Nyssa, declaring his intentions to kill her, take the lotus, and remain as Ra's al Ghul. This plan backfired on Oliver, who then had to pursue Nyssa and her rogue League followers throughout the streets of Star City. While Malcolm seemed to want to play along with Oliver's little game, there was no way he would part with the power of the ring. Especially not since he put everyone's life in danger and even killed Sara Lance (Caity Lotz) to get it.

Neither Nyssa nor Merlyn wanted to concede their terms, so Oliver came up with a new plan. After he captured Nyssa and bargained with Malcolm, he told them they should settle who should be Ra's al Ghul the League way: Trail by combat. Nyssa and Malcolm both agreed to fight one another for the ring, but strangely Oliver stepped in to fight on Nyssa's behalf. The scene was all too familiar. Oliver vs. Malcolm Merlyn on a roof in Star City. It was as if "Arrow" took everyone back to season one -- but so much has happened since then. Since Oliver didn't believe in killing he had to find a way to loose Malcolm of his ring without ending his life. So, he played the Vader card: Oliver cut off Malcolm's left hand, the hand that wore the ring of Ra's al Ghul. This was good enough for Nyssa, who then handed over the lotus. Thankfully the lotus did heal Thea, and Thea started to return to her normal self.

Everything seemed to wrap up nicely, until Nyssa decided to destroy the ring of Ra's and release the League of all of its assassins. This was the second time Nyssa demolished the League's power. The first time was when she destroyed the Lazarus Pit. This time she destroyed the very power that led the League in the first place. Nyssa is a phenomenal character, and Katrina Law plays her perfectly, but her father was right about her: she would be the League's undoing. Malcolm, it would seem, could live without his hand, but his belief in the League was so powerful, that watching R'as' ring melt was almost worse than watching Thea die. The descrution of the League made Malcolm furious, who, after blaming Oliver for letting Nyssa win, went to Damien Darhk (Neal McDonough) with information. The information that Merlyn gave Damien was the truth that Oliver had a son named William, who was more precious to him than even the love of his life, Felicity Smoak (Emily Bett Rickards.) This turn of events was a complete and total game changer for any theories about who is in the grave a few months from now. If William dies, or if his mother dies, Oliver could go on killing spree against H.I.V.E. that would make season one's "list" look like child's play.

The episode concluded with Felicity making a huge decision about the fate of her father, Noah Kuttler (Tom Amandes,) who had shown up at the end of last week's episode, "Unchained." When Noah arrived at Palmer Tech to see Felicity's product release, she thought he was there to see her. As she quickly discovered, he was there to reveal himself to her as "The Calculator." He knew that she was "Overwatch" and he wanted to use her skills and her access to Palmer Tech. He tried to woo her with his stories of hacktivism and try to presume they could have some kind of relationship over their mutual appreciation for hacking, but Felicity saw right through it. When she gave him a tour of the Palmer lab, he hid a data copier in it so he could steal the blueprints for future technology. Despite wanting a relationship with her long, lost father, she decided to turn him into the authorities. He had been a wanted criminal for over a decade, and Felicity decided that he was too dangerous to be let into her life and into her city. The episode concluded with Felicity and Oliver renewing their promise to finish campaigning for mayor and to finally get around the planning their wedding.

Next week's episode, "Code of Silence," centers on the growing relationship of Felicity's mom, Donna and Laurel's dad, Quentin. It also showcases Oliver and Felicity's plan to move forward with the wedding. As seen in the trailer below, Damien Darhk has a dangerous surprise for Team Arrow, which may jeopardize Thea, even though she just got healed up. "Oliver (Stephen Amell) and team uncover HIVE's plan to take out Team Arrow once and for all. With HIVE's next attack imminent, Lance (Paul Blackthorne) wonders if Donna (guest star Charlotte Ross) is safer without him in her life. Meanwhile, with the wedding fast approaching, Oliver begins to feel guilty that he hasn't told Felicity (Emily Bett Rickards) about his son. (#414). Original airdate 2/17/16."

"Arrow" airs on Wednesdays at 8 p.m. on The CW.