"Because It's All for You" plunges into a shocking mystery when bride Sayaka is poisoned during her wedding reception, amidst the height of her happiness. Photographer Sakuraba quickly ascertains that poison was mixed into the champagne. The groom, Hayashida Kazuomi, teams up with Sakuraba to uncover the culprit, suspecting someone among the wedding guests. As their investigation unfolds, the true colors and deep-seated hypocrisy of those closest to Sayaka, including her best friend and her own mother, begin to emerge. Simultaneously, disturbing glimpses of Sayaka's own dark and hidden past come to light. This gripping thriller reveals that every single person involved harbors secrets, leading to a cascade of shocking truths that will redefine everything.