The Jade Mask (1945)

Respected detective Charlie Chan receives a critical government assignment to investigate the mysterious disappearance of scientist Harper, who was developing a vital serum. The situation escalates when Harper is found murdered, prompting Chan to unravel a web of intrigue. Among the prime suspects are the scientist's sister and his loyal butler. As Chan delves deeper into the case, he must navigate a maze of motives and secrets to uncover the truth behind the murder and the serum that could alter everything.