There are many hidden hints and clues in Forensic Pioneer 4. 1. Chronology: There are many scenes in the movie that take place at different times, such as many cases in the previous four seasons and new characters. These time clues could help the audience understand the background of the story and the development of the characters. At the same time, they also revealed some unsolved problems. 2. Character relationships: There are many complicated relationships between the characters involved in the movie, such as family, friends, colleagues, etc. These relationships can help the audience understand the interactions and emotions between the characters, but also reveal some unsolved problems. 3. Evidence Collection: There are many scenes in the movie that involve the collection and investigation of evidence. This evidence could come from multiple sources such as eyewitnesses, investigators 'reasoning, external sources, and so on. The evidence could help the audience understand the investigation process and legal procedures, but it also revealed some unresolved issues. 4. Suspense and Puzzles: There are many suspense and puzzles in the movie, such as the protagonist's background, hidden criminal motives, mysterious organizations, and so on. These puzzles could help the audience understand the story background and character development, while also increasing the interest and appeal of the movie. 5. Hints and Metaphors: There are many hints and metaphor in the movie, such as digital passwords, suggestive smiles, meaningful conversations, etc. These hints and metaphor can help the audience understand the theme and emotions of the movie, but also reveal some unsolved problems.