Call Me Tonight

Rumi, a high school girl who works nights at a hotline, answers a caller named Ryo Sugiura who insists he becomes a destructive monster whenever he is aroused. She is amused by his confession and secretly attracted to the troubled caller. The bizarre premise of his problem sets the tone for their dangerous, offbeat connection.

During their night together in a diner, Rumi uses the date to seduce Ryo, testing his boundaries and curiosity. The moment of closeness triggers Ryo's transformation right there, revealing the monster he tries to hide. The encounter confirms the reality of his condition and deepens their complicated attraction.

Frightened but also determined, Rumi flees with Ryo, deciding to try a radical plan: habituate him to sexuality so the arousal-driven monster can be contained. They escape into the city streets and empty avenues, evading curious eyes. Their bond grows as they commit to a dangerous, unconventional cure.

They press on into the city's red-light district, continuing their date while pursuing a method to control the beast through gradual exposure and intimacy. Ryo reveals he can hold back the monster with enough will, if he stays connected to Rumi. The plan is fragile, but it gives them a shared purpose amid the night’s neon maze.

Maki Nohara, a yakuza woman and fellow horror fan, starts tailing them after witnessing Ryo’s transformation. She is also the older sister of Rumi’s classmate Oyuki, who becomes obsessed when she sees a photo of Ryo. Oyuki begins to plot and tries to blackmail Rumi into bringing Ryo to her.

Oyuki, hungry for control, attempts to coerce Rumi with a blackmail ploy after seeing a photo of Ryo. When Rumi refuses, Oyuki orders her gang to kidnap the couple, escalating the danger they face. The stage is set for a brutal confrontation that will test loyalties and love.

In an abandoned building, the kidnapped couple is left in a perilous trap: Rumi is forced to endure assault by Oyuki's men while Ryo is subdued and unable to prevent the nightmare. The assault triggers a deeper monster awakening in the creature. The pair's bond is pushed to the breaking point as escape seems unlikely.

Maki arrives, warned by her henchman Hayata, and races to the building to confront the kidnapping. She fights through the chaos to reach Rumi and Ryo, hoping to protect them and uncover Oyuki's scheme. The tense confrontation sets the stage for a final reckoning between the rival sisters and the monster inside Ryo.

Oyuki’s torment triggers a brutal transformation in Ryo, amplifying the monster’s power as he loses control. Ryo’s fear and rage spike, complicating any chance of rescue or rescue by Rumi. The situation becomes a life-or-death battle with the monster threatening them all.

Maki fires a bazooka at the monstrous form, but the creature regenerates and continues its pursuit, forcing the trio to flee toward the building’s roof. The battle spills onto the rooftop, where every decision could decide Rumi’s safety and Ryo’s humanity. The monster advances, leaving little room for mercy.

Desperation and love culminate when Rumi hands Ryo a keepsake from their date, a small symbol of their connection. The emotional plea cracks the creature’s hold, and Ryo summons the inner strength to expel the alien entity threatening them. The alien is sent away into the night sky, freeing Ryo from possession and restoring his humanity.

Some time later, Maki encounters the now cured Ryo and Rumi, who are living together with a wary peace. Oyuki has joined Rumi’s company, yet she remains unstable. The ending hints at ongoing danger as Oyuki transforms into a monster herself, causing turmoil in a nearby building.