Paul Bergot, a Belgian soldier during World War I, drives away a German soldier with his slingshot, then reads the latest letter from his pen pal, Mary Brown, an American with whom Paul has fallen in love, even though they have never met.  While he is reading, Paul is captured by the same German soldier, who, after the Armistice, takes Paul along when he emigrates to America to become Zandow the Great, a vaudeville strong man.

After their arrival, Paul searches for Mary by comparing a poor photograph of her with women he passes on the street.  He is spotted by "Gold Tooth," who slips some stolen money into Paul's coat to elude the detective following her.  The detective is fooled, but when "Gold Tooth" attempts to retrieve the money, she discovers that it has slipped into the lining of Paul's coat.  She then tells him that she is the "Little Mary" for whom he is looking, and although he is dismayed by her worldly behavior, she lures him to her apartment building.  Outside the building, however, Paul attempts to flee, and so "Gold Tooth" pretends to faint, after which Paul gets her up a stairway by holding her on his lap and scooting up the stairs one at a time, backwards.

In her apartment, "Gold Tooth" chases Paul, trying to get the money, while he assumes that she is burning with passion for him.  She gets the money, and Paul leaves to rejoin Zandow, who has been engaged to perform in Cloverdale.  Paul enrages his fellow bus passengers with his ministrations to his cold, but eventually he and Zandow arrive in Cloverdale, where Mary's father, Parson Brown, is leading the fight against Roy McDevitt, a bootlegger and owner of the Palace Music Hall.

Paul soon learns that Mary is in Cloverdale and presents himself to her, after which he is stunned by her confession that she is blind.  Despite his shock, the couple are soon holding hands and sharing jokes.  Zandow, meanwhile, has become drunk and cannot perform, so in order to prevent the audience from rioting, McDevitt dresses Paul in Zandow's costume and thrusts him onto the stage.  Paul entertains the crowd for a while, but when one of the audience members makes a rude reference to Mary, Paul begins a fight which soon escalates beyond his control.  Paul takes refuge on the trapeze onto which Zandow was to be shot from a cannon, grabs a stage backdrop and covers the crowd with it.  When they free themselves, he shoots at them with the cannon, and after many shots, one of which propels McDevitt into a garbage can, the Palace is destroyed.

Soon after, Cloverdale has returned to its former peaceful state, and Paul, now a police officer, begins to walk his beat.  Mary asks to come with him, and when she cries after his refusal, Paul relents and takes her along.  He trips and she helps him up, after which they continue, arm in arm.