Apparently we know where the hostages are: an abandoned building in The Glades. And the police are set up right outside, but there are hidden explosives so they can't go right in. The commissioner is directing a bomb-detecting robot, so Sergeant Lance shows up and mocks the commissioner's plan as being too slow.
Oliver ziplines in and breaks through a window right above the hostages, He frees all four of them and they start to walk out. That was easy! It took him like five minutes, tops. He tells them to go up on the roof. One hostage says, "What about--" Oliver answers, "I'll handle him." I like that she was worried about him. A lot of hostages are just worried about getting to safety.
Oliver creeps through the warehouse until he sees the Black Arrow silhouetted at the other side of a hallway. Oliver: "What do you want with me? Black Arrow: "What any archer wants. To see who's better." They shoot at each other from maybe fifty feet away, and they both duck out of the way. There's some running, and Black Arrow loses sight of Oliver. But then he sees Oliver's reflection in a shard of glass on the floor and shoots him off a catwalk. More shooting! Black Arrow is in a much better costume, which covers his face a lot better. Oliver is soon on the ground and being kicked. Black Arrow says, "I know about the list. And the man who authored it wants you dead!" He bends down to remove Oliver's hood, and Oliver stabs him. With Black Arrow temporarily distracted, Oliver staggers away with arrows sticking out of him. He falls out of a second-floor window and bounces off a dumpster. Lying on the ground, he calls Diggle for help.
Oliver wakes up in a hospital bed, because Diggle got him out of there. He has broken ribs and a concussion. And arrow wounds, presumably! The family comes in. The official story is that Oliver was on his bike and a semi pulled out in front. Thea's mad that he bailed on his party, and Oliver says it seems like the right thing to do. It's a fair point, since Oliver left right after Thea yelled at him about how no one wanted his stupid Christmas party. Walter says that the family is, in fact closer together, which was the goal of the party. Thea says she's not the same person she was five years ago either. Oliver says they should just accept each other. I'm pretty sure they've come to that conclusion in at least two other episodes. And she brought him candy canes. She gives him a hug, which is just the thing you want to give someone with broken ribs.