It turns out Diggle actually has a job to do when Oliver's taking down a gang of thugs seemingly single-handedly. The whole time, Diggle's across the street with some night-vision binoculars telling Oliver where the bad guys are, which goes a long way toward explaining how he's always able to shoot the guy on the catwalk in the shadows. But when the team's done breaking up a counterfeiting ring, Diggle gets snatched by people who work for Amanda Waller. I don't have time to explain how exciting this is, but it's pretty cool. Ms. Waller tells Diggle that his friend Lyla has gone missing in Moscow, where she was looking for Deadshot.
Of course, this means that Oliver, Diggle, and Felicity have to go to Russia to rescue Lyla. Their excuse is that they're going to visit the Moscow office of Queen Consolidated, which immediately causes complications when Isabel Rochev tags along. Luckily, Oliver has no shame in ditching all of his business obligations so he can concentrate on finding Lyla. Isabel is a little annoyed, but after she and Oliver sleep together, she's... about the same, actually. Although now Felicity's really angry and hurt that Oliver is going around having sex with ladies he doesn't even like.
Oliver talks to one of his Russian mob contacts, and it turns out to be the guy who was in the cell net to him on the freighter. Lyla is in the toughest prison in all of Russia, because she was looking for Deadshot. So Diggle purposely gets caught with a duffel bag full of drugs so he can get into the prison. And after fighting with a generic prison gang, he gets thrown into a special punishment room, where Deadshot is already being held. Deadshot kills the guard who's helping Diggle, and now they have to work together. The rest of the plan goes pretty smoothly, and they find Lyla and escape. Diggle doesn't kill Deadshot, and in return, Deadshot says he was hired to kill Diggle's brother by someone or something called Hive.
Back in Starling City, Moira's lawyer tells Thea she shouldn't be dating Roy Harper because it will look bad for her mother's defense. So they break up. Then Moira finds out and tells them to get back together. It's not a great use of screen time. The flashback segments at least show Sara lying to Oliver so he'll reveal that Shado and Slade are still alive on the island. Oh, and Dr. Ivo is looking for some WWII-era stem cell research the Japanese navy was into. That sounds pretty safe and normal, right?
Roy sticks a dart in the wall. This is how he signals The Arrow that he has news for him, but we don't see the results right away.
Instead, Felicity walks into Oliver's office as Isabel Rochev is lecturing him about missing meetings and not signing important documents. I think this is part of Oliver's facade as a rich idiot, but he's also supposed to be saving Queen Consolidated, so maybe he should consider doing his CEO duties. Felicity has trouble interrupting smoothly, so she finally just shouts, "ALERT!" Once she has his attention, she tells Oliver he has plans this evening with Mr. Harper. On their way out, Oliver complains about the low quality of the excuse, but I think he has a responsibility to pay attention to her when she rushes in at night. It's night, by the way. Most of Oliver's scenes at the office are at night, because he always has to go do dangerous vigilante stuff.
Roy watches through binoculars as a black Range Rover stops and disgorges some goons. Oliver (as The Arrow) appears behind him and lectures him about being more subtle when he's supposed to be hiding. I never think Oliver's all that subtle when he's standing on buildings, silhouetted against the night sky, but I guess it's easy to see him when there's a camera pointed at him. Roy's here because there's a counterfeit money deal going on inside a warehouse, and Oliver tells him to stay out of it.
In the warehouse, some printing plates are traded for a duffel bag full of money. But then! Arrow! Arrow! Arrow! The duffel bag of real money erupts in flames and one guy's hand gets pinned to the wall. Diggle is across the street, watching through binoculars and letting Oliver know that there are bad guys above him and on his six. That's good thinking! And I like seeing that Diggle has a purpose when Oliver's laying waste to bad guys. One guy gets out of the warehouse and runs for it, but Roy tackles him and starts pummeling him. He's still mid-pummel when the police roll up, so Roy gets arrested. Other than that, the mission has been successful. But as soon as Diggle puts down the binoculars, some other goons taser him in the neck and kidnap him.
Diggle wakes up in a warehouse. Probably a different one. I choose to believe that Starling City has so many vacant warehouses as a result of the season one earthquake driving businesses out of town. A woman walks in and introduces herself as Amanda Waller. Yay! I usually like Amanda Waller, although this woman is skinner than the usual depiction of her. Diggle complains that "you ARGUS guys" are supposed to be more subtle. But Ms. Waller has something to talk about: Diggle's military contact Lyla has gone missing in Moscow. He asks why she's telling him, and she leans close and says, "Because I know how you and Oliver Queen spend your nights." I like that the show recognizes that Oliver is terrible at having a secret identity. Only the local police don't know who he is, and that's only because Quentin Lance is willfully refusing to see the obvious. Diggle sighs and asks what Lyla was doing in Moscow. Well, she was tracking down Floyd "Deadshot" Lawton, which Diggle figures she was doing for him. Waller says that Lyla is irreplaceable for her, and apparently for Diggle as well. So that's the mission: Diggle is supposed to go to Moscow, find Lyla, and get her back.