Spoilers for Arrow Season 5, Episode 19.
Helix helped Felicity find proof that Adrian Chase is Prometheus, but Oliver became even more concerned about Felicity’s involvement with them. Chase escaped protective custody.
Onto the recap:
Team Arrow try to find Prometheus:
Oliver, the team, and ARGUS follow a tip to an arcade to find Prometheus. Prometheus is not there, but he has been, and there are traps.
After the failed attempt to find Prometheus at the arcade, the group reconvene at City hall. Lyla explains that Chase escaped using a secret tunnel. Oliver tells the press that they are working to find Prometheus, but he refuses to reveal details of the investigation.
Felicity asks Helix for help:
Alena suggests that Felicity break into ARGUS’s network. When Felicity does, she realises that someone in ARGUS tipped Chase off, Agent Pierce
Alena kills Agent Pierce:
The ARGUS agent who tipped Chase off gets into an elevator. He falls down dead when the doors open again. Alena approaches and steals a tag from around his neck.
Lyla and Oliver examine the body:
Lyla examines the body of Agent Pierce and removes something from around his neck. Oliver gets Felicity and Curtis to bring up the security footage in the elevator. Felicity realises that the elevator dropped 40 stories. It was controlled by computer and hacked using a code. Felicity recognises the code and tells Curtis that she will take it to Helix to ask for help.
Rene and Quentin talk to victims relatives:
A man who lost his wife to Prometheus is upset with the way the investigation is going. Quentin promises that they will find Chase. After the man leaves, Rene hopes that there is no one else to see today. Quentin comments that he thought Rene would be more sympathetic, given his situation: Curtis told Quentin about Rene’s wife and daughter, and that Rene has not contacted his lawyer friend, even though it’s been two months. Rene says that he is not ready.
Felicity asks Alena about Agent Pierce. Alena admits that she hacked the elevator, but she didn’t mean to kill him. She says that she needs the key Agent Pierce had to free Caden James: A hacker and their founder who ARGUS locked up without cause or evidence.
Felicity is upset that Alena killed someone, but Alena says that Felicity will help her free Caden from ARGUS because Caden can help her find Prometheus: He was working on a bio-metric tracker that can recognise a heartbeat.
Lyla realises that the key was a fake:
Lyla tells Oliver that the key she found on Agent Pierce was a fake: someone stole the real one. Two are required to access ARGUS, but security is compromised as reprogramming takes 24 hours and the attackers may go after a second key. Lyla says that she has her agents in lock down, but one is in the field. Oliver agrees to escort the agent to safety.
Felicity tries to get Alena to negotiate with ARGUS. Alena refuses. She has hired professionals to get a second key. Felicity realises that Helix are going after the same agent that Oliver and his team are trying to protect.
Oliver lets Helix take the key:
Oliver and the team confront Alena’s hired goons, but Felicity tells Diggle that they have to let them get away with the security key to find Prometheus. Oliver lets them go.
Felicity leaves the team:
Back at the Arrow base, Lyla is furious, and Oliver says that Felicity crossed a line. Felicity is angry and insists that Helix is their best chance of catching Chase. Diggle says that there are better ways to find Chase. Felicity says that her only choice is to help Helix. She leaves.
Quentin talks to Rene about Zoey:
Quentin tries to convince Rene to see Zoey. Rene has full visitation rights, but he has never visited. He says that his daughter deserves better. She was hurt in an accident, and Rene blames himself.
Lyla tells Oliver about Caden James:
Lyla says that Caden is a person of interest. Diggle is not impressed that ARGUS are holding him without him committing a crime or giving him a trial. Lyla insists that Caden is too dangerous to let go.
Diggle says that Curtis knows where the Helix base is: they should go after them. Lyla wants to set a trap at ARGUS and use Caden as the bait instead: With or without Oliver and Diggle’s help. She leaves, and Diggle tells Oliver to try and talk Felicity out of working with Helix.
Oliver talks to Felicity:
Oliver shows up at Felicity’s flat just as she is leaving. He tells her that he understands that she is willing to do whatever it takes, but he asks her not to work with Helix, to work with him to find another way. Felicity refuses and tells Oliver that he will have to stop her.
Oliver helps ARGUS:
Oliver tells the team that they have to stop Felicity. They wait at ARGUS for Helix to attack. John worries that Lyla is becoming like Amanda Waller (the last boss of ARGUS): holding people without trial, crossing lines. He doesn’t want her to go over to the dark side.
Felicity and Alena prepare:
Felicity and Alena are given guns. Felicity is concerned: Alena said that no one was going to get hurt. Alena says that if they do this right, no one will.
Rene sees Zoey:
Quentin arranges for Rene to see his daughter. Rene is initially upset at Quentin, but when he sees Zoey, he agrees to fight for custody.
Lyla’s plan fails:
Helix don’t show up where ARGUS and the team are waiting. Lyla reveals that she moved Caden to another site, which Helix have found and attacked. Oliver and Diggle head to the site, but Diggle is unhappy. The site where Caden is being held is an illegal one.
Felicity and Helix free Caden:
At the warehouse where Lyla hid Caden, Helix arrive. They disable the turrets and laser beams with hacker tablets and use the keys that Alena took from ARGUS to free Caden.
Team Arrow confront Helix:
Oliver and his team take out some of Helix, but Felicity puts herself between Alena and Oliver so that Helix can escape with Caden. Felicity traps Oliver behind the laser wall that she disabled earlier, and leaves the tablet for Curtis to let Oliver out. She apologises and hopes that Oliver will understand, but Oliver says that she shouldn’t count on it.
At the Arrow cave:
When the team return to base, Oliver wants to be left alone: He has no idea what to do about Felicity. Diggle understands with just a look, and Dinah leads a babbling Curtis away.
Rene thanks Quentin:
Rene tells Quentin that he has spoken to the lawyer that Curtis knows to put things in motion to get his daughter back. He thanks Quentin and they head off to get drinks.
Helix abandon Felicity:
Felicity returns to the Helix base to find it deserted. Alena appears on a TV screen and explains that Helix have moved because Felicity’s connection to the Green Arrow is a liability, especially with ARGUS after Caden. Alena has left the heartbeat tracker for Felicity though.
Lyla and Diggle fight:
When Lyla returns home, Diggle says that she promised not to become like Waller, but the job has changed her. Lyla thinks that she does what is necessary to protect the people she loves. Diggle says that last time this fight ended in divorce. He doesn’t know if he can move past this.
Felicity returns to the Arrow base:
Felicity plugs the bio-metric tracker into the computers in the Arrow cave. Oliver arrives, and Felicity explains that Helix froze her out. She insists that Oliver didn’t back her play because he doesn’t trust her. The monitor beeps and homes in on Chase’s location. Apparently, he is in the Arrow cave. The monitor explodes, and Felicity and Oliver are thrown backwards.
Did Helix configure the USB stick that they gave Felicity to sabotage the Arrow base in case the Green Arrow went after Helix and Caden? Alena seemed upset when she spoke to Felicity, and Prometheus could have been working with Helix from the beginning to drive a wedge between Oliver and Felicity…
The explosion was an EMP, and it traps Felicity and Oliver in the Arrow base… but was Helix or Prometheus responsible?