Arrow season 2, episode 15, “The Promise,” aired tonight, featuring a look at how Oliver and Slade’s relationship went bad on the island.
The episode picks up just after Slade and Oliver have been introduced. It seems that Slade made a generous contribution to Moira’s campaign and plans to continue supporting her. The three share a drink, and Slade toasts to friendship.
As the three talk, Slade makes references to the island that only Oliver understands. When Moira asks if Slade has someone special, he replies that there was someone but she passed away a few years earlier. Oliver retorts that he and his mother have dealt with loss and learned to just move on.
After Moira leaves the room, Oliver tries to stab Slade, but Slade stops him just as Thea arrives. Moira, Thea, and Slade head off to look at some of the Queen family art collection, while Oliver trails behind furiously. Thea gives Slade a bit of a tour of the collection while Oliver dials Felicity’s number.
In the Arrow cave, Sara is training Roy with a bow. Felicity answers Oliver’s call and puts it on speaker. Sara recognizes Slade’s voice and realizes Oliver needs help. Diggle pulls out their biggest gun while Sara enlists Roy’s help, as he has mirakuru in his system like Slade.
Diggle lines up a shot outside the Queen mansion. Sara sneaks into the house while Roy enters through the front door, calling for Thea. Roy and Slade shake hands while Sara comes downstairs, much to Slade’s surprise — and maybe a bit of hurt.
The moment is fraught as Roy, Sara, Oliver, and Slade face off, but Slade eventually bids Moira farewell. Oliver volunteers to walk Slade to his car, but Diggle is knocked out at his post. Oliver realizes Cyrus Gold and his ilk were working for Slade. Slade replies that he has his own allies.
When Oliver asks Slade what he wants, Slade replies, “Five years ago I made you a promise. Do you remember? Well, I’m here to fulfill it.”
Back in the house, Moira calls Oliver out on his rude behavior and tells him not to come by the house with that attitude.
Cut to a shot of three monitors filled with camera feeds from the Queen house — Slade planted them during his tour.
The island flashbacks open with a (mostly shirtless) training montage as Oliver prepares to take Ivo’s freighter. As Slade makes plans, Oliver takes Sara aside; he wants to destroy the mirakuru so Ivo can’t have it. Slade, surprisingly, agrees, so they burn the crate.
Meanwhile, Sara warns Oliver that Ivo will try to blame him for Shado’s death to turn Slade against him. She tells him that he he has to kill Ivo before he can do so and cause Slade to snap again.
That night, Slade, Oliver, and Sara share a drink. Oliver asks Sara to tell his family that he’d changed if he dies. Sara, in turn, asks Oliver to tell her family that she died on the Gambit so they’d remember her the way she was.
After a guilt-fueled nightmare about Shado, Oliver dons the hood for the first time while Slade puts on the Deathstroke mask.
On the beach, Oliver ignites a bonfire with a flaming arrow, catching Ivo’s attention on the ship. He sends a couple of his men to the island. Before they split up, Slade reflects that when he and Oliver first tried to get off the island together they were strangers, but now they are brothers.
When Ivo’s men reach the beach, they find Oliver waiting. He runs from them but trips in his escape, and he’s taken back to the ship. In his cell, Oliver befriends Reverend Thomas Flynn before being taken to Ivo. Oliver is strapped to a chair and injected with sodium pentothal (truth serum).
Oliver answers Ivo’s questions, admitting the bonfire was a distraction. He tells Ivo that Sara and Slade are in the engine room, so Ivo sends his men after them. However, we discover that Sara had given Oliver a counter agent to Ivo’s drugs — he was acting.
Sara and Slade, meanwhile, use the parachute to launch themselves onto the freighter’s deck. Oliver gets loose from his captors and, in the ensuing panic, meets Sara and Slade. The three split up, and Sara frees the prisoners. One of them tries to kill Sara, but she’s rescued by Flynn.
Meanwhile, Slade wreaks havoc on everyone he comes across, and Oliver makes his way across the ship. He enters the cabin in an explosion and holds Ivo at arrow point. Ivo, as promised, puts the blame for Shado’s death on Oliver — and Slade overhears the whole thing.
Furious, Slade takes out his rage on Oliver as the ship explodes with fires, gunfire, and violence. Oliver uses the riot as a distraction and meets up with Sara and Flynn. Sara convinces Oliver they need to get back to the shore, so several prisoners jump overboard. But Slade stops Oliver, locks him in a cell, and takes control of the ship.
Those who jumped overboard make it to the beach while Slade has Oliver dragged out of his cell. Slade reveals that he saved some mirakuru then gives Ivo a gun. He demands Ivo show him how he killed Shado, so Ivo points the gun at Oliver while Oliver pleads with Slade.
But before Ivo can shoot, Slade cuts off his hand and has him taken away. He tells Oliver, “You cannot die until you have suffered the same way I have suffered. Until you have known complete despair. And you will. I promise.”
Arrow returns with a new episode on Wednesday, March 19.