Now that Limit has proven itself as a psychological survival thriller, how else can it build on that? How about turning into a murder mystery as well? That's what happens in Volume 4, as the consequences of a major character's death start to play out. Previously, the series had created tension by pitting opposing personalities against each other—geeks versus popular kids, hot tempers versus level-headedness—but the tension in a straight-out whodunit is a different creature entirely. When mistrust arises from life-or-death situations, as opposed to mere high school politics, the story reaches new levels of drama that's sure to impress.

After all, part of the excitement in a survival thriller is that not everyone is going to survive. However, this means more than just mechanically killing off characters, and here, manga-ka Keiko Suenobu employs the tactic of doubt and confusion. Here's the corpse, here's the cackling maniac who probably did it, and ... here's a set of circumstances pointing to a totally different suspect. What makes it so brilliant is that this had been set up from the very first volume: Morishige is portrayed as a sociopathic victim-turned-bully, behaving like a classic villain. Yet her character gets a reprieve in these chapters, suddenly becoming vulnerable—and it all comes to a head when Mizuki tries to "kill her with kindness," forcing Morishige to break down emotionally. Readers might be thrown off by the mood change, and the amount of sappy melodrama that goes into this moment. Still, if there's one thing to be learned from these events, it's that first impressions are often misleading—and that the author may have planned it out that way.

Misdirection and doubt also drive the other subplots in this volume. When Haru is tapped as a possible suspect, she starts to question her own memories—if you can't trust yourself to recall what's been going on, who can you trust? This is Suenobu's other great twist: she isn't just casting doubt on the characters, but about the story itself. Does anyone know for sure what happened, or are people remembering things wrong? With all the intrigue surrounding the characters, their motives, and the events of the last twenty-four hours, Limit completes its transformation into an addictive murder-mystery. And it doesn't stop there: the last chapter leaves more tension and dread hanging in the air, with a second death that hits Mizuki even harder than the first, and a nasty surprise from a character who's been quietly lurking this whole time. Not only does Keiko Suenobu play her cards with precision, but she also knows which ones are yet to be played.

Artwork is another key element in creating the series' uneasy mood. Bold, rough lines and dark shadows take over any part of the story where negative emotions dominate—not only in dramatic death scenes, but even during heated arguments. Just as striking, though, is Suenobu's ability to shift her style 180 degrees: tones become conspiciously lighter and the linework suddenly turns delicate during conciliatory scenes, like when Mizuki tries to soften Morishige's attitude. These dramatic visual changes tell the story as much as the actual twists in the plot, although it never becomes an overbearing gimmick at any point; the top priority is still to present the events of the story clearly. The character designs, although relatively simple, are grounded in enough realism to capture the look of an everyday high school student, with plenty of variations in looks and build. Backgrounds also get a fairly detailed treament, although there are a number scenes where they get left out entirely—a concession to the characters and their interactions being more important than the setting itself.

Despite the deceptive twists and swirling emotions, the dialogue is surprisingly simple—the kids in this series say exactly what they mean, without much embellishment. There are, of course, some irritating touches of vagueness, where a character doesn't know how she feels and so the sentence just trails off. Aside from that, however, the script is straightforward enough that one can even follow the problem-solving portions without having to dig into a verbal minefield. Sound effects and external dialogue are left in their original Japanese, with dramatic font choices that actually add to the story's emotional dimension, while English translations are placed beside these effects without obscuring the action.

If Limit only seemed "pretty good" when it first started out—schoolkids fighting for survival, social mores going out the window, a new spin on familiar concept—then this is the moment it really starts to push into the realm of greatness. The addition of a murder-mystery twists the series into something more than just a survival thriller: this volume casts doubt on whether any of the characters, and even the storyline itself, can be trusted. The sure-handed, stylistically versatile artwork follows along with all the ups and downs of these chapters, and where it's headed next after the closing pages ... who knows? Despite a confined setting and a limited cast of characters, the possibilities of Limit are surprisingly—and frighteningly—wide open.