Lulu, a six-month Labrador, witnesses her owner Nora’s secret murder by seemingly gentle neighbor Kane. The cold-blooded killer leaves no clues, and Detective Arthur takes the traumatized pup home temporarily. Mute yet sharp-sensed, Lulu remembers the culprit’s scent, shoes and every crime detail. For three months, she repeatedly hints at the truth through silent gestures: rushing to Kane’s house, scratching the crime scene wall, and reacting fearfully to him. Slow-witted Arthur misreads her trauma at first, while Kane keeps trying to kill the only eyewitness with traps and framing plots. After countless near-death escapes and Lulu’s hidden key evidence, Arthur finally sees through the lies. He sets a trap, arrests Kane for homicide, and officially adopts the loyal, brave Lulu, forming an inseparable healing bond with the silent little detective.
