Elmer Edgemont, a pants presser, has a crush on Trilby Drew, a stage actress. Dressed in finery borrowed from his customers, Elmer waits to glipse her along bridle paths and at public gatherings. He has seen all 35 performances of her latest play, a Civil War melodrama. In it Trilby plays a belle harboring a wounded Confederate lover, played by Lionel Benmore, who exclaims "A scratch is nothing to a Southern gentleman!" A nasty Yankee officer captures the rebel and threatens to kill him unless Trilby yields to the officer's desire. The first-act curtain falls just as one of the Yankee soldiers, unable to resist the swooned Trilby, steals a lecherous kiss. Elmer lives every moment of the play, to the distraction of those who sit next to him. Earlier, Trilby has ignored Elmer, for Lionel is her romantic interest. But she becomes vexed over Lionel's attentions to a pretty blonde, Ethyl, So Trilby shows Elmer some attention. Encouraged, he comes backstage before the next night's performance. He meets the actor who plays the lecherous soldier, a part he envies. Just then, police appear, looking for the actor. He tells Elmer to play his part, then dives out a window. Elmer puts on copious false whiskers, disguising himself. As he waits to go on, he accidentally pokes a hole with his rifle bayonet in a sandbag. When he gets onstage he turns the melodrama into a face, entering at the wrong time, crawling through backdrops and catching his feet in the scenery. At the big moment, just as he leans forward to kiss Trilby, the sand in the bag runs out, dropping a fly on his head. The audience loves it, but the manager and actors want to kill him. Before they find him, though, he has changed back into his borrowed evening clothes, and they don't recognize him. Meanwhile, Trilby has discovered that Lionel and Ethyl are going to be engaged. In an act of spite, she asks Elmer to marry her that night. He does. At the honeymoon suite, Trilby goes into a furious sulk, climaxed with a screaming fit that sends Elmer retreating into another room. The next evening, at a night club, the newlyweds sit near Lionel and Ethyl. Trilby gets drunk and creates a scene. Elmer patiently takes her home. She passes out, and he has a struggle getting her into bed. He finally succeeds and gently kisses her goodnight, whereupon the bed collapses. The next day, as Elmer playfully crawls into Trilby's room with a stuffed dog, he meets her attorney and Lionel. Trilby has left Elmer and wants a divorce. Outside, when Lionel bousts that Trilby loves only him, Elmer slugs him. Lionel shouts for the police, and Elmer runs, jumping into a cab already occupied by a fleeing robber. The cabbie falls out, and Elmer takes over, driving the cab off a pier at the crook's orders. A gang of rum-runners, the crook's accomplices, haul him aboard their boat. At night, Elmer escapes to a nearby yacht. He becomes a deckhand and is trying to varnish the mast next day when he looks down and sees Trilby and Lionel cuddling below. Horrified, he stays below deck. That night a fire breaks out in the boiler room, and Elmer, after being told to wait for an officers' meeting to finish, finally reports it. Everyone panics. Lionel, fearing for himself, throws Trilby aside, knocking her out. Elmer meanwhile puts out the fire by opening a porthole and letting water pour in. He then discovers that he and Trilby are the only passengers still onboard. Se he puts on the captain's abandoned cap, bails out the boiler room, and reefs the sails for a squall (with some difficulties). But when Trilby tries to hug him in gratitude, he coolly removes her arms. A boat appears. Elmer waves it over. But it is the rum-runners. Elmer has his captain's cap taken away. He tries to keep Trilby's presence a secret, but the cief rum-runner discovers her and tries to make her yield to his advances. Elmer goes into action, knocking out each rum-runner by trickery. But the leader comes to, and Elmer must fight him the full length of the ship - falling off the bow at one moment, floating back to a dinghy towed in the rear, then coming back aboard again. In a flurry of powerful blows, Elmer finally overcomes the man. Overwhelmed at his bravery, Trilby goes to Elmer. He defiantly replaces the captain's hat on his head, declaring, "A scratch is nothing to a Southern gentleman!" Then he passes out in her arms. Next day, to a cheering crowd, Elmer brings the yacht into port, towing the bound rum-runners in the dinghy. Elmer drops Trilby at her apartment building, but she stops him from leaving. "You're going to see a lot of me from now on," she says and takes him inside with her. Passing Lionel at the door, Elmer doffs his hat triumphantly.