Annie and Mary are twin orphans, left in charge of an orphanage. Annie is adopted by a middle-class family and Mary is adopted by a wealthy family. Mary marries a wealthy but dissipated clubman, while Annie becomes the wife of a member of the fire department. Mary is afflicted with heart trouble. Annie knowing that her husband needs a new watch, decides to purchase one for his birthday. Her actions in attempting to buy it excite the suspicions of her husband. That day Mary's home catches fire and her husband being away with some male and female friends, leaves the maid all alone with her mistress and who, upon seeing the fire, is panic stricken and rushes out leaving Mary to struggle alone. Heart trouble overpowers her and she falls back on her bed dead. Annie's husband arrives and he mounts the ladder to Mary's room. Breaking through the window he dashes into the room and, seeing a woman on the bed, goes to her. One glance at her and he believes her to be Annie. Carrying her to a place of safety, a physician is summoned, who pronounces Mary dead. The poor fireman staggers away. Later in the day he wanders home. Annie who sees him coming, conceals herself behind a curtain. He enters his house and crushed by his terrible blow, decides to end his troubles forever by blowing out his brains. Annie comes from her place of concealment and shows him his birthday gift and he, stunned by her unexpected appearance drops the revolver back in the drawer and clasps her in his arms. Annie never knew.