A plot could be that Edward, the cop, is framed for a crime he didn't commit. He has to clear his name while on the run from his own department. This could lead him to discover a conspiracy within the police force that is much bigger than he thought. Maybe he teams up with a hacker who helps him find evidence to prove his innocence. Another idea is that Edward is assigned to a special task force dealing with organized crime. He has to build relationships with informants, some of whom are not entirely trustworthy, and navigate the dangerous underworld of crime bosses and their henchmen.
One idea could be that Edward, as a cop, is assigned to protect a key witness. During this time, he discovers a complex web of secrets and has to fight against both the criminals who want to silence the witness and some corrupt colleagues. Another plot could be Edward investigating a series of mysterious murders in the city where all the evidence points to a supernatural force. He has to overcome his disbelief in the supernatural to solve the case. And also, Edward could be a rookie cop who gets involved in a big drug - bust operation and has to prove himself to his more experienced partners.
Well, perhaps Edward as a cop stumbles upon a human trafficking ring. He goes undercover to infiltrate the ring and rescue the victims. Along the way, he meets a love interest who is also involved in the fight against the traffickers, either as a journalist trying to expose them or another undercover agent. Or, he could be investigating a string of high - profile burglaries where the thief always seems to be one step ahead. Edward then has to use his wits and detective skills to catch the elusive burglar, which might involve working with an old - school detective who has his own unorthodox methods.