映画的なホラーアクション短編：高校の体育館での発生

Cinematic horror-action short film set in a Japanese high-school gym after hours, late afternoon. Opens with an immediate strong hook, maximum dynamic camera work, grounded practical-effects style. Polished wooden court, volleyball net half-lowered, equipment bags and balls scattered. A girls' volleyball team packing up. Coach in a tracksuit with a whistle around her neck. Janitor in a faded work jacket near the far wall with a mop cart. Warm late-day sun through high windows, muted authentic color grading, natural diegetic sound throughout, tension score entering immediately. [0-1s] Hard cut: a player at mid-court suddenly jolts, dropping a volleyball; it slaps the wood as she gasps sharply. [1-2s] Close-up: veins turn deep red, racing up her neck and across her face in the gym light. [2-3s] Her eyes snap open, fully red - she lunges and bites the teammate reaching to help her. [3-4s] The bitten girl cries out. Nearby players recoil; sneakers squeak as they scramble back across the court. [4-5s] The bitten player convulses hard on the floor, veins spreading fast across her neck and arms. [5-6s] She rises seconds later, eyes red, joining the first; both turn toward the cluster of teammates. [6-7s] Panic hits the gym. Players scream, climbing over the lowered net and scattered bags toward the exit. [7-8s] The coach spots it from the sideline, shouting urgently in Japanese: 「非常口へ！急げ！」 ("To the emergency exit! Hurry!") [8-9s] The janitor slams his mop cart aside; the metal frame clangs off the wall as he grabs a heavy steel stand from a folded referee platform. [9-10s] The coach snatches a folded metal chair, moving fast across the court toward the fleeing team. [10-11s] They reach the emergency doors, shoving the crash bars; daylight and hallway air flood in. [11-12s] Players pour out into the corridor, some slipping on the threshold, others sprinting clear. [12-13s] The two infected slide across the polished floor, then push through the last of the fleeing girls, lunging toward the nearest one just outside. [13-14s] The janitor swings the steel stand hard, striking the first infected across the shoulder, sending her stumbling back onto the court. [14-15s] The coach swings the folded chair into the second, knocking her against the doorframe. [15-16s] SLOW MOTION insert: the first infected lunges again; the janitor sidesteps and drives the stand down with a solid blow. [16-17s] She collapses onto the court, motionless. The volleyball nearby rolls to a stop. [17-18s] The second infected recovers, charging the coach; she braces and swings the chair in a wide arc. [18-19s] The impact connects hard, sending her sprawling against the lower bleachers. [19-20s] She tries to rise; the janitor rushes over, delivering a final strike alongside the coach. [20-21s] She goes still. Both adults stand over them, breathing hard, weapons still raised. [21-22s] Wide shot: players huddled in the sunlit hallway just beyond the open doors, shaken but safe. Empty gym behind them, dust in the light. [22-24s] The coach lowers the chair, scanning the group, counting heads to confirm everyone's out. [24-26s] The janitor checks the two motionless figures on the court, cautious, then nods once. [26-28s] A stray volleyball rolls past his shoe and stops. [28-30s] Final shot: coach and janitor exchange an exhausted look. The team slowly regroups in the hallway under the late-afternoon light. Cut to black. Natural diegetic sound throughout - gasping, screaming, sneakers on wood, crash-bar slam, metal impacts, heavy breathing, a distant school bell, hollow gym echo - layered with a tense instrumental score that builds through the chaos and eases into thin relief at the end. No text overlay, no watermark. Maximum dynamic camera variety - close-ups, wide court shots, low tracking across the polish, handheld only on impacts. Slow motion reserved only for the final takedown blows. Realistic shake only during physical hits. Natural late-day gym color grading: warm window light, cool shadows under the bleachers.