This week on "Fighting Fire with Fire," Oliver Queen faced impeachment as his connection to a cover-up was brought under investigation. Amidst these allegations of corruption, Oliver was targeted by the Vigilante who, up until this episode, was believed to be District Attorney Adrian Chase. All of that changed when Prometheus revealed himself to be Chase! It was a crazy twist that no one saw coming, considering Chase's comic book legacy lies with the Vigilante. In addition to that shocking reveal, Oliver made the rash decision of throwing the Green Arrow under the bus and blaming him for the death of Billy Malone. While this may have cleared Oliver's name for the time being, it will come at a cost for Team Arrow. Curtis paid a price this week -- his marriage -- which sadly came to an end after Curtis made a breakthrough with his T-spheres. The final moments of the episode set up a kidnapping arc that hopefully won't end with anyone's death, but this is "Arrow," so you just never know #SaveSusanWilliams.

Prometheus Revealed

Arrow Adrian Chase

Tonight's first big twist was the moment we've been waiting for since Season 5, Episode 1: the true identity of Prometheus. For months the identity of the masked "throwing star killer" has been teased -- was he Roy Harper? Deathstroke? Tommy Merlyn? -- none of the above. After Vigilante tried to kill Mayor Queen, Prometheus attacked him, claiming that Oliver was "his" kill. Prometheus and Vigilante then got into a fight, which led to Vigilante being thrown off a roof. Then, in a surprising move, Prometheus unmasked himself as DA Chase. That means Chase has been playing a very long, very well planned con on Oliver. Not only has Prometheus tried to sabotage the Green Arrow's team (for killing his father,) but he has also been playing Oliver from inside the Mayor's office. It's clear now that because Chase was part of the Billy Malone cover up, that he's the one who leaked the information to the press.

This reveal bring up a few questions. First, if Chase is not the Vigilante, who is? Second, what IS Chase's game here? He wants to discredit Oliver, sure, but why? Is Chase purely driven to get revenge on his father's death, or is there more to the story here? We know that Talia al Ghul trained Chase at some point, will the flashbacks in Russia reveal something in the coming episodes about why Talia trains men with daddy issues? Also, if he was seeking to discredit the Mayor, how will he react to Oliver avoiding an impeachment charge? Perhaps that's why he chose to kidnap Susan Williams at the end of the episode. If you're curious about Chase's motivations, you can also check out  this interview CBR did with actor Josh Segarra about the Prometheus reveal.

Oliver Chooses Mayor Queen

In the midst of being put on trial for willfully covering up the Green Arrow's involvement in the death of Billy Malone, Oliver was forced to make a choice. Star City was looking for a scapegoat, someone to blame for the death of this cop. Chase offered to take the blame himself (which is interesting, considering we know who he is now,) Thea even offered to step in to shoulder some blame. But Oliver couldn't let that happen, so he had to choose between the Green Arrow and Mayor Queen, and he chose Mayor Queen. In a press conference during the jury's deliberation, Oliver put full blame for Malone's death on the Arrow. Oliver even went so far as to call the Green Arrow a "cop killer." While this admission spared him his career as Mayor, it made the Arrow public enemy number one, again. It was so meta watching Oliver deliver a speech about the Arrow "failing the city," because he looked so much like the Quentin Lance of seasons past. Diggle seemed assured that Team Arrow would be fine, since they've been on the most wanted list before, but still, something about that scene felt so cold, like Oliver putting the Arrow on the sacrificial altar of Star City -- which is exactly what Chase/Prometheus wanted. It's rare that a villain gets such an upper hand against Oliver and so far Prometheus is winning this game.

Fighting Fire With Fire

Thea Felicity Arrow

Since the second half of this season began, both Thea and Felicity have been on a similar journey. Last week, they had the opportunity to blackmail Susan Williams so she would drop her case against Oliver, and they did. They both knowingly planted evidence on a woman who was ultimately doing her job. When Oliver found out, he cautioned Thea against doing anything that would resemble her mother's darker sides. This week, Thea and Felicity had the chance to blackmail someone again, this time a politician who could be the swing vote in Oliver's impeachment trial. Both women were tempted to use the information on Pandora to blackmail him, but Oliver again warned Thea of the ramifications. When Diggle found out that Felicity was going to help Thea, he told her that when you fight dirty, when you fight fire with fire, you get burned. Thea took this advice and chose not to get burned -- instead she tendered her resignation and decided to take some time for herself to heal. Felicity, however, took the opposite road. At the end of the episode, she contacted her source at Helix and agreed to join their hacktivist ranks. It's interesting to see how vigilante darkness has affected these women over the last five seasons and how they are both choosing to cope with it in different ways.

One Step Forward, Two Steps Back

The episode concluded with two heartbreaking moments. First, Curtis, who was so excited about getting a breakthrough in his T-Sphere design, was served divorce papers by his husband Paul. All throughout the episode, Curtis was looking forward to reconciling with Paul. He was also excited because his T-Spheres -- which are straight out of the comics -- helped geo-locate the Vigilante. He and Rene had some great moments where they exchanged laughs over the Spheres, including their failures and successes. Curtis' joy was dampened when his husband Paul asked for a divorce. The other heartbreaking moment came when Thea gave Oliver her letter of resignation. Thea had been so close to blackmailing someone to save Oliver's political career, but she knew that it was wrong. Thea called herself "broken," and admitted that she needed to get help. Thea is a strong, important member of this team, hopefully her time of healing doesn't keep her from Team Arrow for too long.

Rescuing Susan Williams

Next week during the episode "Checkmate," Prometheus' true identity will be revealed to Oliver when Talia al Ghul arrives in Star City. Hopefully Oliver will save Susan in time, otherwise he may have another "Queen's Gambit" on his hands.

OLIVER SEEKS THE TRUTH — Oliver (Stephen Amell) gets closer to the truth about Prometheus. Meanwhile, Helix refuses to continue helping Felicity (Emily Bett Rickards) until she does a favor for them. Ken Shane directed the episode written by Beth Schwartz & Sarah Tarkoff. Original airdate 3/15/2017.

Airing Wednesdays at 8 p.m. ET/PT on The CW, “Arrow” stars Stephen Amell, Emily Bett Rickards, David Ramsey, Willa Holland, Paul Blackthorne and Echo Kellum.