'Arrow' Recap: "What We Leave Behind," Season 5 Episode 9

There's a traitor on CW's "Arrow." They've been feeding information to the enemy and they're ready to carry out the attack in "What We Leave Behind" the fifth season's ninth episode.

Oliver comes to the conclusion that Prometheus knows all of Team Arrow's identities after an attack on Curtis. His plan is to pick off the team one by one.

With the help of Detective Malone, Felicity is able to find Prometheus' link to Oliver in their past.

Artemis has been collecting information on every member of Team Arrow for Prometheus. She wants to watch him kill the Green Arrow but Prometheus has no intention of ending Oliver's life. Oliver has invited the reporter to the office benefit. Felicity introduces Malone to Curtis and his husband, Paul.

Diggle, his son, and the rest of Team Arrow are having dinner together in the cave. Evelyn gifts everyone with a Christmas stocking. Curtis has to leave early because Paul thinks he's cheating on him. Prometheus attacks Curtis right outside.

Curtis wakes up in the hospital. Felicity and Oliver send Paul out to talk to Malone in order to talk with Curtis. Malone wants Felicity to stay with him to protect her. The drug Curtis was injected with is one Oliver remembers. It was a case from back when Team Arrow was just Oliver and Diggle.

The identity of Prometheus suspiciously seems like Justin Clayborn, a man The Hood killed. The team goes to check out an old warehouse that belonged to Clayborn. The Green Arrow gets locked in a room, alone, with Prometheus.

Wild Dog and Artemis rush to his location. When they get their Artemis reveals whose side she's really on. The two disappear as the rest of the team arrives.

Felicity gets a text from Malone. He's got a hit on Prometheus. It's information that she already has. Rene and Rory are left to test ashes they found at the warehouse. Paul demands the truth out of Curtis.

Needless to say he doesn't approve of this new career choice. The ashes belong to Clayborn, meaning he's not under the Prometheus mask.

Malone searches the old warehouse for any overlooked clues. He finds a picture of a baby. He's able to send it to Felicity before Prometheus pops up behind him.

Felicity has no idea why Malone would send him the baby picture but he won't respond. In the past, Diggle warns Oliver that if he keeps killing he might have to face consequences. The DA comes up to Oliver, he wants permission to shoot on sight. Felicity has figured out that Prometheus is Clayborn's son and he's had four years to learn everything that Oliver has.

Thea has suited up for this showdown. Rory called Curtis and he goes to support the team with Felicity.

Oliver remembers a location Felicity found for him years ago. He believes that's where Prometheus is hanging out. He heads over, alone.

Prometheus has recreated all the deaths The Hood committed on the night he killed Clayborn. It all leads to Prometheus standing in the place his father died in. He chases him to a room filled with mirrors. Prometheus taunts him and when he steps out from behind the mirrors, Oliver shoots to kill. Unfortunately, it's not Prometheus under that mask but Malone. Oliver must go back to the team with the news of what's happened.

Felicity doesn't blame him. Paul leaves Curtis. Oliver goes to see reporter lady.

He shares his nightly events and she comforts him. Diggle gets a call from Lyla but when he gets home the police are waiting for him. Oliver goes back to the lair to find Laurel, alive.

"What We Leave Behind" was full of revelations. The "Arrow" mid-season finale pulled another ghost from Oliver's past. Tune in in the New Year to find out what happens next.

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