Fact1: average citizens to catch criminals without being noticed, Fact2: Men are hated by underworld due to constant meeting, Fact3: crook never gets busted for crime due to lack of evidence, Fact4: Dan overhears to catch conversation and hurries to Marty for protection only him in midst of robbery, Fact5: Marty returns to town in rage after finding out about Dan and Myrtle 's engagement
Output: The film focuses on the Plain Clothes Men, a group of detectives dressed up as average citizens to catch criminals without being noticed. They are especially hated by the underworld due to their constant meeting, during which suspects are analyzed and interrogated extensively. Among the staff is Dan Coghlan Lon Chaney, a police officer with flat feet and a tough disposition, who is unsatisfied with the lack of adventure. As he is about to quit his job, he is noticed about a croaked jeweler. When arriving there, he finds Skeeter Carlson Wheeler Oakman, a crook who never gets busted for a crime due to a lack of evidence. Dan decides to follow him, and after talking to Skeeters lowlife girlfriend Bessie Mae Busch without gaining any information, he prevents Skeeter from seducing Myrtle Sullivan Anita Page, an innocent flapper who finds excitement in hanging out with crooks. Dan has lately assigned himself as Myrtles caretaker, and he disapproves of her boyfriend Marty Carroll Nye, a dapper gangster without a job. When Skeeter is out of town for two days, Dan graps this opportunity to manipulate Bessie. After convincing her that Skeeter will soon dump her for Myrtle, Bessie admits that he croaked the jeweler. Without wasting any time, Dan sets out to bust Skeeter and his men, only to find out that one of them is Marty. Shortly after, Bessies body is found, and Dan is convinced that Skeeter is responsible for her death, considering that she was going to testify against him. The case against Skeeter is dismissed by the court, and he immediately reveals his plans on murdering Marty. Dan overhears this conversation, and hurries to Marty for protection, only to catch him in the midst of a robbery. Even though he is able to turn him in, Dan orders the police to leave Marty alone and helps him to take his first, tentative steps on the straight path. Before leaving town, Marty wants to meet Myrtle one more time and sends her a letter, but Skeeter reads it before she can. He forces himself up to her, but is disturbed by police raid. Before they open the door, Skeeter fires a shot through it  which croaks a cop  and gets away. Upon finding out that she will testify against him, Skeeter sets out to kill her. Meanwhile, Dan tells Myrtle against better judgment that he loves her and then proposes to her. Even though she is actually in love with Marty, Myrtle accepts, mostly out of gratitude for all that Dan has done for her. Afterwards, Dan leaves to find Skeeter, and catches him and his men preparing for a getaway. It results in a giant shootout, during which several policemen and gangsters are killed. Skeeters men give in after being attacked by tear bombs, but Skeeter finds a way to escape to the rooftop. Dan follows him there, and after another shootout, Skeeter is killed. Meanwhile, Marty returns to town in rage after finding out about Dan and Myrtles engagement. He proposes to Myrtle, but she decides to stay loyal to Dan. Dan realizes that she loves Marty, and allows them to be together.