The Hidden Moon is a macabre suspense thriller with a BL twist. The series mostly works. Early episodes shroud the story with supernatural elements that deliver a sense of foreboding. A palpable dread permeates the characters' interactions. Mysteries emerge that require sleuthing by our protagonists. Some of these unknowns pertain to Real World events while others transcend reality to seemingly touch upon ethereal planes. The series even broaches the Big Mystery: what happens when a person dies? Amidst all the paranormal uncertainty, a BL romance struggles to emerge. That subplot is almost an afterthought, however, as this series is a suspense thriller first; a romance, only to change pace between supernatural set pieces. That de-emphasis of the BL plot will disappoint viewers interested primarily in MM courtship. Their loss. If the idea of a slow-burn spooky ghost story appeals, the ten hours of The Hidden Moon will be worth the time to watch. If such fare is not your cup of tea, then you don't need to know the twisty turns anyway.

The writer of reviews must choose betweeen two variants of the form. One style pitches the text toward readers who have seen the material and cannot therefore be spoiled (full disclosures with double-barrel critiques). The alternative aims to reach those readers seeking out the review to help them decide whether to start watching. This group can be spoiled, so the reviewer should be circumspect (strategically withholding details and pulling punches in the criticism). To preserve the sense of macabre, to maintain the air of suspense, and to preserve potential thrills, this review will pursue the latter path. The production team behind The Hidden Moon mostly got right the macabre, the suspense, and the thrills. They do not deserve to have that effort undermined by a comprehensive debrief of every strength and weakness. So, this review will risk vagueness by imparting fewer details than customary. Indeed, I encourage anyone deciding whether to watch to avoid investigating specifics. The less you know about this one, the more you will enjoy it. With that disclaimer, onward with my purposefully vague critique.

The series opens with five young people arriving at an Obligatory Old House. An Old House with a reputation. An Old House that may be haunted. They have come to investigate these rumors. Before the first episode ends, the group begins to experience unexplained events themselves. (That's five time-worn tropes already! Happily, none of them is a BL trope!) Over the next several episodes, the team tries to uncover explanations for the unusual goings-on. The pacing proves uneven. Not all episodes are equally spooky. A couple in the middle really drag. Arguably, the early episodes suffer from a bad case of writers trying to create mystery by simply not explaining anything. That tactic led to characters confused and frustrated with their situation. This reviewer suspects many viewers will share that sentiment. Hooking the audience with juicy details might have been a better strategy. Unexplained phenomena may rightfully vex characters, but they alienate viewers when dragged through too many consecutive episodes. Fortunately, viewers who stick with the series will be rewarded. Three strengths save the series from the reliance on hoary tropes and the problems with pacing.

First, the technical arts creative team (cinematography, direction, lighting, editing, music) understood their assignment. Overcoming gaps in story logic, the vibe remains consistently tense--brooding and unsettled. The sense of macabre persists during the slow episodes, so that when the story recovers vigor, the suspense has never descended into farce or hokiness. Few viewers of The Hidden Moon will ever nominate the series as an exemplar of the macabre suspense thriller genre's best. But it is absolutely solid work.

Second, later episodes grow stronger. They deliver cogent story beats, unexpected twists, and better interactions among the characters. When the payoffs arrive from those unexplained mysteries of the early episodes, they prove worthwhile. Episodes 8-9 (penultimate) stand out in particular.

Third, the series has a time travel element unusual in the suspense genre. One member of the Thai Scooby Gang experiences paranormal weirdness in two timestreams. For unknown reasons, Khen is shifting between the past and present of the Obligatory Old House. In both timelines, an angry female specter targets him for special attention with the kind of ghostly violence that threatens Khen's life. Fortunately, one denizen of the 1910s timeline is able to intervene on his behalf. Mas is the handsome son of the homeowner. As Mas and the strange visitor from "another world" grow better acquainted, bonds of affection grow between them.

The dynamic between the two young men, separated in time by about a century, provides the BL storyline. Perhaps during episodes 6-7 the macabre even takes a backseat to the courtship. Nevertheless, the BL story remains mostly threadbare. The two would-be lovers, after all, recognize that living in two different worlds poses an insurmountable challenge to their future prospects. And veteran viewers of K-drama and BL alike are surely aware that ghost-human romance has little chance of achieving a happy ending. An undercurrent of "why bother?" haunts the scenes where Mas and Khen deepen their emotional bonds. Young love, inevitably, will persist against all admitted logic. And so it is with Khen and Mas. The BL tale adds some emotional heft to The Hidden Moon's endgame, and it is the duo's interaction that will restore balance to each universe. BL viewers who endure the suspense and supernatural shenanigans in the hopes of a romantic denoument suffused with happy endorphins will see their patience rewarded. Kind of. I'd say more...but spoilers.

In closing, The Hidden Moon isn't primarily a BL series. Rather, it is a supernatural thriller that tossed in a BL romance. Substitute a straight romance, and the underlying tale of macabre would require no alteration. In the final analysis, I'd argue that the series succeeds as a thriller even more than it succeeds as a romance. Full credit to the production team for that success, for I do not belive they worked from a lavish budget. But they deployed their resources wisely, resulting in a finished product that may well be an instance where the whole surpassed the sum of its parts. It is not a great series, but it is certainly very good. It is worth the ten-hour investment of your time to watch.