[Note: This post contains spoilers.]

“The Riddle of the Sphinx” is the first truly great episode of Westworld’s second season, a distinction that’s even more impressive when one considers that it’s the first time that co-showrunner Lisa Joy has sat in the director’s chair. It’s uncommon to find a top-level television writer who is also an excellent director, but in this episode Joy – who, remarkably, has never helmed anything before – evinces superb storytelling instincts and some truly cinematic formal chops. It helps, of course, that “The Riddle of the Sphinx” is centered on a jaw-dropping revelation, and writers Gina Atwater and Jonathan Nolan do a commendable job of structuring the entire episode around that reveal without veering into (too much) indulgent wheel-spinning.

“Sphinx”’s central drama is the story of James Delos (Peter Mullan) and his futile attempt to cheat death using technology similar to that of the Westworld hosts. The repetition of James and William’s (Jimmi Simpson) interactions inside the elder Delos’ windowless, retro-futurist quarters-cum-prison is a brilliant bit of storytelling, one whose lean intensity is amplified by the writers’ shrewd decision to stage it exactly three times. In the first instance, the fundamentals of James’ situation are established, but a sense of menacing mystery is also present, evoked by the men’s slippery conversation and the faintly uncanny aura of Joy’s mise-en-scène. (An early sign of “Riddle”’s excellence: a hypnotic, 360-degree pan around the chamber, lingering on the still-life details of James’ environment, while the Rolling Stones “Play with Fire” spins on a mod turntable.)

The second iteration of this scene raises the viewer’s hackles by means of discrepancies in blocking and dialogue compared to the first, before closing with an unsettling science-fiction twist: James has been dead for some time, and the company has been unsuccessful in its efforts to coax his digitally preserved mind to “take” to a new, 3D-printed body. Finally, in the third repetition, the scene’s premise is extended to its logical, horrific conclusion, one signaled the moment that “old William” (Ed Harris) appears at James’ door. It’s now been decades since James’ physical demise – Trial 149, to be exact – and William has concluded that the elder Delos’ immortality scheme is an uneconomical pipe dream. Delos, it seems, has been developing other, more profitable uses for the host technology, and the company’s subsidization of a cantankerous old man’s resurrection is now effectively over.

Apart from their formal distinction, what’s fascinating about these flashback scenes is how they both confirm and crush one of the more popular fan theories that has emerged in recent weeks: namely, that Delos’ host technology is being used for some sort of secret immortality project, a possibility foreshadowed last season by Robert Ford’s (Anthony Hopkins) references to the biblical story of Lazarus. The transference of the dying James’ human mind into an artificial body was indeed one of Delos’ ventures, but it turns out have been little more than an indulgent side project, and one that ultimately proved impossible to perfect. Intriguingly, this twist reinforces another prominent theory: that the host technology has been repurposed – likely by William – for a kind of “body snatchers” scheme aimed at the global elite, in the fashion of Futureworld (1976), the largely forgotten theatrical sequel to Westworld (1973).

Most of the other subplots in “The Riddle of the Sphinx” revolve around these flashbacks, either narratively or thematically. The episode puts a disturbing coda on James’ story by having it intersect in ghastly fashion with the near-past journey of Bernard (Jeffrey Wright) and his former Behavior co-worker Elsie (Shannon Woodward), who it turns out has been chained up in a remote sector of the park since Season 1. (She’s understandably wary, given that it was Bernard who attacked and imprisoned her, even though he only did so under Ford’s orders and has no recollection of the event.) The pair discover another secret Delos outpost, where Elsie manages to keep the still-malfunctioning Bernard operational a bit longer with a cortical fluid injection. In a scene that swerves into straight-up horror, they eventually stumble onto the final, critically glitchy iteration of “James”, who has escaped his cell and slain his overseers,

Meanwhile, William and his host companion, Lawrence (Clifton Collins Jr.), have a run-in with Major Craddock (Jonathan Tucker) and the remnants of the Conferados who escaped last episode’s massacre at Fort Forlorn Hope. Craddock and his underlings have essentially taken Lawrence’s hometown Las Mudas hostage, under the assumption that the village's Mexican revolutionaries possess a secret weapon cache that the ex-Confederate guerillas covet. This sets up a gratifying Sergio Leone-inspired showdown between Craddock and William, who initially seems to sell out the townsfolk before finally turning his revolver on the drunken Confederados. It’s foolish to attribute every event in Season 2 to Robert Ford’s master plan, but it’s hard not to see the Las Mudas events as the game’s attempt to nudge William ever-so-slightly toward the white hat role he abandoned long ago.

There’s a subtle but resonant contrast between the chilly amorality exhibited by, on the one hand, William in his interactions with James, and, on the other, the William seen at Las Mudas, who bristles not only at Craddock’s smug, sadistic good-ol’-boy schtick but also at the sight of Lawrence’s innocent wife (Olga Aguilar) being terrorized. The episode connects these two sequences in other ways, with references to the suicide of William’s wife, Juliet, and with the double meaning inherent in William’s invocation of “fidelity” (i.e., both moral faithfulness and the accuracy of a reproduction). The notion of fidelity is further echoed in Bernard’s tale, as his memories, cognition, and loyalties grow ever more scrambled and the revelations regarding his role in Ford’s final, posthumous gambit become more ominous.

Joy deftly weaves together these three major subplots, without relying on the sort of relentless cross-cutting that another director might have used to create a sensation of feverish action where none truly exists. Instead, she uses the longer running time afforded to the “The Riddle of the Sphinx” to linger on each sequence, allowing the tension to swell marvelously. Westworld is often described as a “puzzle-box” show – a label that has been both a compliment and a criticism – but this episode is an exemplar of twisty sci-fi plotting that advances and elaborates on the story, rather than simply functioning as a parlor trick for its own sake. There’s nothing in “The Riddle of the Sphinx” that feels superfluous: just a tight, evocative chapter in a saga that grows increasingly engrossing and terrifying.

Some miscellaneous observations:

• The only other subplot that “Riddle” touches on is that of Rajworld guest Grace (Katja Herbers), who, along with Stubbs (Luke Hemsworth) and several other humans, has been rounded up by the Ghost Nation hosts. She’s released after some cryptic comments from the tribe’s chieftain-slash-prophet, Akecheta (Zahn McClarnon), who appeared in “Reunion” as one of the hosts at Argos' first demonstration for Logan. Later Grace crosses paths with William, Lawrence, and the revolutionarios, triggering another surprise: she is William’s adult daughter.
• One of the central mysteries of Season 2 is how many of the hosts have achieved true consciousness. Delores, Maeve, and perhaps Bernard have found their way through Arnold’s metaphorical maze, but the rest of the androids still seem to be stuck in their pre-programmed loops to some extent, even if they’ve turned newly murderous. In this episode, the series offers the first indication of another rank-and-file host who remembers events prior to their last memory wipe: Lawrence recalls William telling him the story of his wife’s suicide, even if he doesn't really understanding how he can recall it.
• Westworld has always been steeped in the fundamental questions of modern Western philosophy, a discipline whose origin is often informally attributed to the French thinker René Descartes’ observation, “cogito ergo sum” (“I think, therefore I am.”) The epistemological principles (and paradoxes) articulated by Descartes are touched on obliquely in almost every episode of the series. However, “Riddle” vividly references one of the philosopher’s seminal thought experiments: the Evil Demon, an omnipotent entity that creates and manipulates every detail of the observer’s reality with the intent to maliciously deceive. (In various altered and corrupted forms, this idea has become a staple of speculative science fiction, where it is often described as the “brain in a vat” hypothesis.) The garbled words spoken by James’ decrepit host-body evoke Descartes’ demon, imagining a monotheistic universe in which the only godhead is a malevolent trickster:

They said there were two fathers. One above, one below. They lied. There was only the devil. And when you look up from the bottom, it was just his reflection … laughing back at you.