In this gripping psychological thriller directed by Alec Su, a desperate act of protection spirals into a chilling game of cat and mouse. When a single mother, played by Ruby Lin, finds herself in a violent confrontation, her reclusive and brilliant neighbor, mathematics professor Shi Hong, portrayed by Wang Kai, steps in to help cover up the incident. His meticulous plan creates a seemingly perfect alibi, but it soon attracts the sharp intellect of his old university rival, physics professor Tang Chuan (Zhang Luyi). As Tang, alongside determined detective Luo Miao (Xu Jiayi), begins to peel back the layers of the case, a tense battle of wits unfolds between the two genius friends. The film masterfully builds an atmosphere of suspense and intellectual duel, exploring the depths of devotion and the terrifying precision of a mind capable of designing the perfect crime, where every solved equation only leads to a more dangerous mystery.