Back to the island. Oliver makes fire! Which is tough because it's raining. He hears someone coming and covers his fire before grabbing his knife and scampering off. A soldier with an automatic weapon finds the smoke. He might be a ninja, actually, since he's all in black and wearing a black ski mask. He speaks into a radio, "I have contact. Two klicks southwest." Oliver hides behind a tree.
Back to Starling City. We're in another burning warehouse. The bad guy whacks a fireman over a railing. While he's dangling by one hand, Oliver does some showy moves on the way in. This takes long enough for him to lose his grip and fall into the fire. Oliver and the bad guy fight. It's pretty brief, but Oliver sees a firefly tattooed on the back of the bad guy's hand. Then the bad guy throws a bomb and vanishes.
Oliver sits and mopes in the Arrowlair. The whole point of having a secret lair is so you can mope in it. It's either that or go find a high building to mope on, like Batman. Oliver flashes back to the island, and that time he was hidden behind a tree. He attacks the ninja-soldier, who immediately makes him drop his knife. The two of them roll down a hill and fall in a pool of water. Modern Oliver takes off his hood and takes out his phone to call the Arrowphone, which, again, is clearly an iPhone. It's on "Starling Wireless," so it can't be that hard to track. He tells Laurel that there's a tattoo of a firefly, but that that doesn't narrow it down much, because everyone on this one engine had that tattoo.
Diggle has a knack for summing things up: "So Laurel's on her own against a murderer who burns people alive?" The question comes up of whether Oliver is 100 percent and is ready to fight. They solve this by some quick Kung fu. Yes, he's still good enough to beat up Diggle. Diggle says the other archer took away Oliver's heart or something. Oliver gets a text from Tommy and leaves to go do something for the fundraiser. This scene didn't do much, but the point is that Oliver's doubting himself.
The next day, Laurel and Oliver bump into each other at the fire department. He's there for something about the fundraiser (or "gala" as he calls it) and she's there to clean out Danny's locker. They talk about Tommy's request to have a drawer in her home. This is weird. Remember that they're exes. Oliver should not be opining on this stuff. She tells him that their fears control them. Very deep.
Inside, Laurel talks to the fire chief. She has a picture of eight firemen who called themselves "The fireflies." The chief shrugs, even though four of the eight are dead. And three of them died in the last six weeks! The other one? "Garfield Lynns. He died two years ago in the Nodell Tower Tragedy." Oliver comes back and asks what the Nodell Tower Tragedy was. It was a 22-story building that was built on the cheap. A gas line blew and the whole thing came down, killing 34 civilians and six firemen. The scene kind of peters out from there as the fire chief leaves and Laurel brushes off Oliver. She pulls out the Arrowphone. Oliver, who apparently carries his secret phone everywhere, answers in the background of the shot. He tells her, "It's my turn."