The story unfolds between a real-world campus and an alternate dimension known as the Undertow. By day, they are deskmates, childhood friends, transfer students, and seemingly ordinary students. By night, they are dragged into an otherworld filled with desire demons, gambling games, contracts, and rules of death, struggling to survive through awakened abilities and deadly dungeons. Jace Cole’s run of bad luck begins when he is pulled into the Undertow while playing basketball—a dimension crawling with desire demons, where death can come at any moment. Worse still, he is rescued by a stranger. When the aphrodisiac pink mist takes effect and his mind slips out of control, that stranger drags him into a water tank and forces himself on him under the guise of saving him. The worst part: he records everything. The next day, that same stranger transfers into Jace’s class and becomes his deskmate. Sebastian Thorne smiles as if he were perfectly harmless, slowly activates the voice recorder, and says: “Jace Cole, do you often break into other people’s rooms at midnight, begging them to sleep with you?” Jace, blushing furiously, replies: “…Can I apply for a new deskmate?” From that moment on, their ordinary campus life becomes inseparable from their life-or-death struggles inside the Undertow. One hides his panic behind sharp words; the other advances one calculated step at a time. One wants to run, while the other insists on keeping him by his side. Inside the Undertow, they fight their way through deadly dungeons together. Outside it, they sink deeper into ambiguity, testing, threats, and uncontrollable desire. Main Characters Jace Cole Tanned Athletic Student｜Male Lead｜POV Character｜Combat Lead A student athlete who is pulled into the Undertow while playing basketball. After being poisoned by a desire demon’s pink mist, he is saved by Sebastian Thorne—and from that moment on, becomes hopelessly entangled with someone he was never meant to meet. Sebastian Thorne High-IQ Young Master｜Second Male Lead｜Tactical Commander｜Main Romance Interest A wealthy and highly intelligent young man who saves Jace when he loses control under the effects of the toxin—and gains leverage over him in the process. After transferring into Jace’s class and becoming his deskmate, Sebastian appears gentle and harmless on the surface, but is actually calculating, composed, and always several steps ahead. Jade Turner Childhood Best Friend｜Heightened Five Senses｜CP Shipper｜Comic Relief Jace’s childhood friend and closest confidante. She jokingly tells him to “give in to Sebastian for the sake of happiness.” After the Undertow descends, her five senses become enhanced, allowing her to witness the drama from the very front row. Quinn Nash Junior｜Clue Character｜Tragic Figure｜Truth Trigger The fourth person pulled into the European dungeon, with such a faint presence that almost everyone overlooks him. He admires Jace and treats him like an older brother, but during the midnight amusement-park gambling game, the truth is revealed: Quinn’s overwhelming desire led him to sign a contract with a demon and trigger everything. The Dealer Unknown Boss｜Rule Revealer｜Worldbuilding Interpreter The human opponent in the midnight amusement-park gambling game. Mysterious and dangerous, he reveals the underlying rules of the Undertow: people with intense desires can make equivalent exchanges with demons. Those who survive and clear the game gain supernatural power.

Jace Cole remains the tanned athletic student and POV character, pulled into the Undertow while playing basketball. After being poisoned by a desire demon's pink mist, he is saved by Sebastian Thorne—and from that moment on, becomes hopelessly entangled with someone he was never meant to meet. His habitual 'I'm fine' is a running gag that should always carry a sting. His agency must be preserved; his choices, even reluctant ones, should drive outcomes. Sebastian Thorne is the high-IQ young master, tactical commander, and main romance interest. He saves Jace, gains leverage, and transfers into his class as a deskmate, appearing gentle but calculating. His intelligence must be shown through scene structure—noticing rule wording, penalty details, or the one player The Dealer ignores. Crucially, he should be wrong when emotion enters the equation; his blind spot is Jace. New consequence direction: The community demands that Sebastian's first real consequence be tied to the tools he used for control. The recorder becoming evidence against him is the leading candidate—poetic justice that tastes expensive. This must land in dialogue later, and the morning-after scene must show the cost. Jade Turner is Jace's childhood best friend with heightened five senses, a CP shipper, and comic relief. She jokingly tells Jace to 'give in to Sebastian for the sake of happiness.' Her enhanced senses make her the perfect audience surrogate, able to puncture Sebastian's controlled persona. She should clock emotional truths before anyone else and then pretend she is joking. Jade must not reset after dungeons; she should become jumpy around certain sounds, carrying trauma forward. Quinn Nash is the junior, clue character, and tragic figure whose overwhelming desire led him to sign a demon contract. He admires Jace like an older brother. Quinn should not be forgiven by the plot just because he is sad. His admiration can be sincere and still become dangerous. The story must hold the contradiction: understanding how he got there while acknowledging he hurt people. Quinn should become harder to notice when he is ashamed, and his loneliness should explain his choice without excusing the damage. The Dealer remains the unknown boss, rule revealer, and worldbuilding interpreter. He explains the Undertow's equivalent exchange: intense desires can create bargains with demons, and survivors gain power. He explains rules as if he is being helpful, which makes it worse. His explanations should be clear enough for viewers to argue about choices, not confusion. New addition: The Dealer's rule reveals should be technically useful in the moment but become traps later. He teaches tactics that should not be used, gives answers only after making Jace admit what he wants, and notices Quinn without warning others why that matters. Every explanation scene doubles as future damage.