Triangle Cafe follows the story of waitress Tamaki who engages in a secret relationship with her colleague Kurono at the café where she works. Unbeknownst to them, their friend Ohashi, who harbors feelings for Tamaki, frequents the café regularly. When Kurono becomes aware of Ohashi's affection, he manipulates the situation by provoking Ohashi to express his love for Tamaki. Through a series of provocative actions, including Tamaki serving Kurono in a state of arousal, Ohashi becomes aroused himself. As tensions rise, another figure, Tomoe, enters the picture, adding a new dynamic to the complex relationships at play. The question remains: will Ohashi find the courage to confess his feelings to Tamaki amidst the unfolding drama?