More a cautionary moral tale than anything else, Conscience makes use of a setting that was to become a horror movie favourite: the chamber of horrors. Persuaded to elope by her lover Eric, Eleanor Donelly defies her police officer brother to go to New York, where the young couple are married. Soon deserted by Eric and desperate for food for her baby, Eleanor tries to steal a bottle of milk. Fleeing in terror from a policeman, she takes refuge in a chamber of horrors. Coincidentally, fallen among disreputable companions, Eric has meanwhile accepted a wager daring him to spend a night in the same chamber of horrors. In the morning, seeing Eleanor in the shadows as she wakes and rises, Eric dies of fright while Eleanor goes mad.

John Lane is a prosperous businessman, a widower, who lives in a large house with his seven-year-old daughter Betty. Lane has an enemy, one Ben Hartley, who, by the aid of some forged papers, threatens to expose Lane and put him in prison. The night of the story opens with Lane receiving a letter from Hartley, who demands $10,000, to be paid at midnight, that night. Lane has not that much ready money in the house, and no way to get it. He thinks it all out and decides to commit suicide. He stands before a mirror and is about to pull the trigger, when Bill, the burglar, steps into the room, stopping him.

Advised by his friends to seek a second wife so that his children, Helen and Dolores, may know a mother's care, Sir Edward Tilbury marries Phyllis, the daughter of Lady Olivia Gower, a leading social light in Calcutta.

Miss Marbury comes on deck and looks haughtily at Mrs. Cray, an attractive young widow, half suspecting that she has her steamer chair. When she finds that she is mistaken, she ties a large red ribbon upon her own chair, which is situated between Mrs. Gray on her left and Mr. Martin, on her right. Miss Marbury is quite annoyed when little Dolores and Helen, Mrs. Gray's two playful children, come to settle a dispute over the ownership of a tennis ball. Tom Blake stops to greet Mrs. Gray and plays with the children, making them forget their animosity.

Miss Marbury comes on deck and looks haughtily at Mrs. Cray, an attractive young widow, half suspecting that she has her steamer chair. When she finds that she is mistaken, she ties a large red ribbon upon her own chair, which is situated between Mrs. Gray on her left and Mr. Martin, on her right. Miss Marbury is quite annoyed when little Dolores and Helen, Mrs. Gray's two playful children, come to settle a dispute over the ownership of a tennis ball. Tom Blake stops to greet Mrs. Gray and plays with the children, making them forget their animosity.

The Baron Lafitte is in love with and proposes to Adelaide Burton, daughter of Andrew Burton, a wealthy manufacturer. Clara Lane, a newspaper reporter, has been assigned to watch the movements of the Baron. She is further instructed to make a scoop of their movements. Tom Drake is in love with Clara, and is her persistent follower throughout.

Etta Lang, a chorus girl, is the principal support of an invalid mother and her sister and brother, not only working at the theater, but looking after their small boarding house. Among their lodgers is Brutus Bellamy, an old actor. He becomes interested in the girl, and offers to teach her acting. She learns rapidly. She arrives at the theater late and is abused by the stage manager, Joseph Burton. Cecil Wentworth, one of the backers of the theater, takes her part and becomes interested in her.

An exceptionally capable girl, Trixie Joyce, proves a great help, to her mother, a widow with a large family of girls. They receive a proposition from Henrietta Joyce, Mrs. Joyce's wealthy sister-in-law, to take Trixie as a companion, feed and clothe her and in place of wages, send her mother an allowance sufficient to support the rest of the family. Both realize it is the solution of a hard problem, and Trixie accepts the offer. Henrietta is close-fisted and selfish in money matters, but she also has a strain of morbidly-romantic sentiment in her nature, so the largest part of Trixie's work is reading aloud to her mistress quantities of swashbuckling, mid-Victorian novels.

As childhood sweethearts, David Horton and Beatrice Elton are inseparable. Fifteen years later Beatrice goes abroad and while there is heartbroken to learn that David has married Margaret Forsythe, a social climber, Margaret starts to entertain on a lavish scale.

Jovial and big-hearted, Jim Brice, of the Howard Detective Agency, is sent to trap bribetakers in a nearby city.