The plot for Forensic Heroes contains a mixture of various themes. The mysteries include Who Killed Tim Sir's wife?, The Tai Po Corpse, Murders for Justice and Where is Tim Sir? The series included many serial killers. However, of all the crimes, there were two very important ones. "Who Killed Tim Sir's Wife?" had two possible suspects, however, the murderer turns out to be a nurse who accidentally poisoned her. This causes Tim's heart to break, but it is a lucky chance for him to fall in love with Siu-Yau. "Where is Tim Sir" was the last and most important mystery. A clown, Tracy's only true friend, abducted Tim. The clown puts him in a port container with seemingly limited air supply, no water and food supply and a camera connected to a laptop, stored in a disc and new clips sent to Forensics everyday show Tim trying to create a fire to attract the rescuers using friction. But Forensics has only three days to find Tim before he dies of thirst and hunger. Siu-Yau is especially worried and fearful as she has fallen in love with him. The clown is caught, brought to Forensics to be interrogated, but before any information is extracted from him, he kills himself. All seems lost. However, while Forensics is searching, Siu-Yau looks at the laptop screen with Sam. Then the lights lighting the container up dim and a small hole is seen coming through the container. This sparks new hope in Siu-Yau and Sam, who check the position of the sun and find out where Tim is. Still, that is not narrowed down enough. Tim is wearing a watch that could reflect sunlight coming through the hole and start a small fire, which the rescuers would see. They are unaware that Tim is waiting to die. Tim sees his wife, Charlie, in a dream. She asks him what he is doing in the world of the dead. Tim says that he is ready to give up and leave the earth. However, Charlie tells him she is sure he can do it and leaves. He returns to reality for a short moment, but soon is back in the dream... Tim this time dreams of his true love, Siu-Yau. He says he is tired of suffering on earth, but Siu-Yau holds his hands and tells him others are waiting for him, and he has to pull through. This gives Tim enough confidence to raise his arm to the sunlight, and start a fire. The air force that is helping to find Tim Sir, finds him in a container. Tim is hospitalized and he tells Siu-Yau that it was her that he saw that made him keep on going rather than giving up. Siu-Yau rejects Tim sadly. Ding-Ding and Sam decide to buy a house together and is it there that Sam proposes to Ding-Ding. There is a party to celebrate the wedding of Ding-Ding and Sam. There, Siu-Yau finally faces her true feelings for the man she loves and accepts a date from Tim. Just then, Tim and Sam's phones ring, and they are called off for a case...
