Reviewed by Phil Boothman.

Well damn, Arrow, you really pulled it out of the bag with this one. Just as last season’s “The Odyssey” kept us firmly on the island for the episode’s running time and was one of the more memorable instalments of that season, so “The Promise” takes us deep into the trauma of what really happened on Lian Yu and provides an action-packed and intense barnstormer of an episode.

So after Slade’s appearance in the Queen household at the end of last week’s episode, he takes it upon himself to take a guided tour of the mansion and all the art contained within. The tour is one of the most hideously awkward situations Arrow has ever portrayed, as so much is left unsaid: Oliver is simultaneously fuming with the very idea that Slade is not only still alive, but has also found his way into the Queen household, and icy towards Moira because of the ‘thing’ about Thea; while Slade is being outrageously flirtatious with Moira because he knows it will get under Oliver’s skin; and Thea is bumbling along being a happy little ray of sunshine in the whole messy cloudbank of feelings and flirtation, completely oblivious to all the tension mounting around her. It’s an odd series of scenes as it becomes almost farcical in comparison to the island flashbacks that comprise the bulk of the episode, albeit a farce that is laced with a deep-seated sense of dread about what is to come. Nonetheless, the tone never feels forced or overtly hilarious, and provides a nice contrast to the time we spend on the island throughout the episode.

Speaking of which, we rejoin Team Island (which is a way worse team name than Team Arrow) as they prepare to board Ivo’s freighter, and talk strategy. The first step is to burn the remaining Mirakuru, which Oliver and Sara do a little bit carelessly as Sara discusses her plan with Oliver: she tells him that he needs to kill Ivo even though Slade wants him kept alive, because if he survives then he will tell Slade about Shado’s death and it will ruin everything. Oliver reluctantly agrees, and they head back to the plane to share a pre-battle drink of fine Australian rum with Slade, which apparently has a vaguely hallucinatory effect on Oliver as he dreams of Shado telling him that it is all his fault and stabbing him a bunch of times with a big scary knife.

But this only seems to spur Oliver on, and he dons the hood for (chronologically) the first time as Team Island gear up: Slade then follows suit by grabbing the red-and-black Deathstroke mask from his gear, and they head towards the freighter which, we are swiftly reminded, is still full of prisoners. Ivo orders the Russian prisoner, Oliver’s Mafioso friend, to be brought to him, and Ivo threatens to remove his eyeball for his ‘research’. Research which, we later learn, is all in aid of saving his wife, who is not only dying but also disapproves of Ivo’s choices, believing it would have been better if he had stayed with her. It’s an interesting moment that adds some pathos to Ivo’s story, and a reason for his almost fanatical search for the Mirakuru, but at the same time does not excuse his actions on the island or make him any less of a villain in this instance.

Anyway, after a couple of false starts Oliver manages to light a fire on the beach (in the same way as he does to get rescued in the pilot episode), and Ivo is distracted from his eye-gouging for long enough to send some men to get Team Island. Unfortunately, Oliver is not quite the badass he grows into yet, and trips over a root while running from them, and getting captured by the pirates. In his cell he meets Hendrick, a nasty bastard who can do impressive one-armed pull-ups, and Reverend Thomas Flynn (who seems like he should be a character from the comics but I can’t find any information about him anywhere, so I would assume that he is, in fact, an original character), who has a pet mouse and is slightly friendlier than Hendrick.

Soon he is taken to Ivo and injected with sodium pentathol, a truth serum which will force Oliver to reveal his secrets: fortunately the whole thing was a ruse, and Sara gave Oliver some kind of salve which nullifies the effects of the truth serum, and he sends the pirates down to the engine room while Sara and Slade board the freighter by parachute and free all the prisoners. Slade goes to take out the pirates, which he does with brutal efficiency, and Oliver heads off to kill Ivo, but he finds himself unable to do so. Unfortunately, Ivo confronts Oliver with what happened to Shado, and Slade happens to be standing behind him: it goes badly, and after a quick rumble Oliver goes to flee the ship with Sara and the prisoners, but is held back by Slade who claims the freighter as his own, reveals that he saved the Mirakuru from the box on the island, cuts Ivo’s hand off and makes Oliver a promise: that he will make Oliver feel complete despair and then kill him.

Meanwhile in the present day, Sara overhears Slade’s voice on Oliver’s phone and informs Felicity, Diggle and Roy of who it is, and they head down to the Queen house to stop him. Unfortunately, Slade’s men take Diggle out before he can shoot Slade, and it is revealed that the reason for Slade’s visit to the house was to plant hidden cameras around the place to keep an eye on the family.

Verdict: 10/10

A truly game-changing episode both on the island and off, with some spectacular set-pieces along with something we’ve not yet seen on Arrow: a single villain both in the present day and in flashbacks. When combined, all these elements mean that “The Promise” is one of the best episodes not only of this season, but of the entire show thus far.